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    <title>topic Audio issues with Communication Panel in Contact Pro</title>
    <link>https://community.sinch.com/t5/Contact-Pro/Audio-issues-with-Communication-Panel/m-p/18448#M578</link>
    <description>&lt;H1&gt;Symptoms&lt;/H1&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;You may come across different kinds of audio issues in Communication Panel (for example, the first call of the day being muted).&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H1&gt;Solution&lt;/H1&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Check the following settings on the user’s workstation.&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;H2&gt;Disable Windows power-saving settings&lt;/H2&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;New Windows versions introduce more aggressive power-saving behaviors. USB headsets may be in low-power mode on first use, causing the first call to be muted.&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;These settings can be in multiple places, depen&lt;SPAN&gt;ding on the computer&lt;/SPAN&gt;. Go through all of the following.&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Power options:&lt;/SPAN&gt;&lt;/P&gt;
&lt;OL&gt;
&lt;LI&gt;Go to &lt;STRONG&gt;Control Panel&lt;/STRONG&gt; (view by &lt;STRONG&gt;Large icons&lt;/STRONG&gt;) &amp;gt;&lt;STRONG&gt;&amp;nbsp;Power Options &amp;gt; Change plan settings&lt;/STRONG&gt; (of the active power plan) &amp;gt;&lt;STRONG&gt;&amp;nbsp;Change advanced power settings &amp;gt; USB settings &amp;gt; USB selective suspend setting&lt;/STRONG&gt;.&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Set both &lt;STRONG&gt;On battery&lt;/STRONG&gt; and &lt;STRONG&gt;Plugged in&lt;/STRONG&gt; to &lt;STRONG&gt;Disabled&lt;/STRONG&gt;.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;/OL&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="Niina_P_5-1749725566523.png" style="width: 400px;"&gt;&lt;img src="https://community.sinch.com/t5/image/serverpage/image-id/6573iD2346B97DF69296C/image-size/medium?v=v2&amp;amp;px=400" role="button" title="Niina_P_5-1749725566523.png" alt="Niina_P_5-1749725566523.png" /&gt;&lt;/span&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Device Manager:&lt;/SPAN&gt;&lt;/P&gt;
&lt;OL&gt;
&lt;LI&gt;&lt;SPAN&gt;Go to &lt;STRONG&gt;Control Panel&lt;/STRONG&gt; (view by: &lt;STRONG&gt;Large icons&lt;/STRONG&gt;) &amp;gt;&lt;STRONG&gt;&amp;nbsp;Device Manager &amp;gt; Universal Serial Bus controllers&lt;/STRONG&gt;.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;LI&gt;Edit the properties of each controller with “Hub” in the title.&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Select the &lt;STRONG&gt;Power Management&lt;/STRONG&gt; tab.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Deselect&lt;/SPAN&gt; &lt;STRONG&gt;Allow the computer to turn off this device to save power&lt;/STRONG&gt;.&lt;/LI&gt;
&lt;/OL&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="Niina_P_0-1749726271871.png" style="width: 400px;"&gt;&lt;img src="https://community.sinch.com/t5/image/serverpage/image-id/6580i623D4536F92B1540/image-size/medium?v=v2&amp;amp;px=400" role="button" title="Niina_P_0-1749726271871.png" alt="Niina_P_0-1749726271871.png" /&gt;&lt;/span&gt;&lt;/P&gt;
&lt;H2&gt;&amp;nbsp;&lt;/H2&gt;
&lt;H2&gt;Install headset manufacturer-specific drivers and firmware&lt;/H2&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;The &lt;STRONG&gt;Brands&lt;/STRONG&gt; selection in Communication Panel audio settings can cause problems if the manufacturer-specific headset drivers and firmware are not installed.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="Niina_P_2-1749723964481.png" style="width: 400px;"&gt;&lt;img src="https://community.sinch.com/t5/image/serverpage/image-id/6569i5A872290FB51F602/image-size/medium?v=v2&amp;amp;px=400" role="button" title="Niina_P_2-1749723964481.png" alt="Niina_P_2-1749723964481.png" /&gt;&lt;/span&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;Make sure that drivers and firmware have been installed before selecting the brand in Communication Panel audio settings. If the drivers and firmware have not been installed, select &lt;STRONG&gt;Other Brand&lt;/STRONG&gt;. Otherwise, the integration may not work as expected and it can cause various other problems.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;You can find more information about prerequisites for different brands in &lt;A href="https://docs.cc.sinch.com/cloud/operation-guide/en/oxy_ex-1/common/headsets.html" target="_blank" rel="noopener"&gt;the Operation Guide document&lt;/A&gt;.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H2&gt;Ensure the browser has permission to use the microphone&lt;/H2&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Windows 11 has tightened app permission handling for microphones. On first use, the system may delay or block microphone access.&amp;nbsp;&lt;/SPAN&gt;&lt;SPAN&gt;This can cause the first call to have no outbound audio (agent can’t be heard). Audio works after the first conversation. &lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;Ensure that the browser has permission to use the microphone:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Chrome: &lt;STRONG&gt;Settings &amp;gt; Privacy and security &amp;gt; Site settings &amp;gt; Microphone&lt;/STRONG&gt;&lt;/LI&gt;
&lt;LI&gt;Edge: &lt;STRONG&gt;Settings &amp;gt; Cookies and site permissions &amp;gt; All permissions &amp;gt; Microphone&lt;/STRONG&gt;&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;We also recommend agents to:&lt;/SPAN&gt;&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;&lt;SPAN&gt;Close Communication Panel at the end of each workday.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Test audio by placing a test call after a Windows reboot or recovering from sleep mode.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H2&gt;In on-premise environments: check the following in your infrastructure in addition to the workstation settings&lt;/H2&gt;
&lt;H3&gt;&amp;nbsp;&lt;/H3&gt;
&lt;H3&gt;NAT binding timeout (UDP media ports)&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;NAT/firewall closes UDP port bindings during idle periods (for example overnight). In the first call of the day, the RTP stream is sent to a now invalid NAT mapping, resulting in one-way or no audio.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;To fix this:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Enable RTP keep-alive on the AudioCodes SBC and/or SIP endpoints.&lt;/LI&gt;
&lt;LI&gt;Configure frequent enough NAT binding refreshes (for example, every 15-30 seconds).&lt;/LI&gt;
&lt;LI&gt;Use symmetric RTP if supported.&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;Codec mismatch or delayed negotiation&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;Codec negotiation failure or delay in SDP exchange on the first call may cause missing audio.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;To fix this:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Verify codec priorities and make sure common codecs (for example, G.711 and Opus) are aligned across systems.&lt;/LI&gt;
&lt;LI&gt;Make sure there's no asymmetric codec handling on the first session.&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;SBC media session not properly initialized&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;The first media path may not get properly opened due to the SBC being in a dormant or idle state, or media anchoring not being fully active.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;To fix this:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Check if media-anchoring or early media support is properly configured.&lt;/LI&gt;
&lt;LI&gt;Enable media timeout settings or pre-establishment of RTP on the SBC.&lt;/LI&gt;
&lt;LI&gt;Ensure ICE/STUN/TURN is used if endpoints are WebRTC-based or behind NAT.&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;Ensure that the latest firmware is installed on the SBC&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;It is always a good practice to keep SBC firmware as up to date as possible.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;General diagnostic steps to investigate the issue&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Check SBC syslog and trace files for the first call SIP and RTP behavior.&lt;/LI&gt;
&lt;LI&gt;Use tools like Wireshark or SBC's built-in trace tools to verify:&lt;/LI&gt;
&lt;UL class="lia-list-style-type-circle"&gt;
&lt;LI&gt;SDP negotiation&lt;/LI&gt;
&lt;LI&gt;RTP stream establishment&lt;/LI&gt;
&lt;LI&gt;NAT behavior&lt;/LI&gt;
&lt;/UL&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;</description>
    <pubDate>Thu, 12 Jun 2025 13:16:52 GMT</pubDate>
    <dc:creator>Niina_P</dc:creator>
    <dc:date>2025-06-12T13:16:52Z</dc:date>
    <item>
      <title>Audio issues with Communication Panel</title>
      <link>https://community.sinch.com/t5/Contact-Pro/Audio-issues-with-Communication-Panel/m-p/18448#M578</link>
      <description>&lt;H1&gt;Symptoms&lt;/H1&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;You may come across different kinds of audio issues in Communication Panel (for example, the first call of the day being muted).&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H1&gt;Solution&lt;/H1&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Check the following settings on the user’s workstation.&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;H2&gt;Disable Windows power-saving settings&lt;/H2&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;New Windows versions introduce more aggressive power-saving behaviors. USB headsets may be in low-power mode on first use, causing the first call to be muted.&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;These settings can be in multiple places, depen&lt;SPAN&gt;ding on the computer&lt;/SPAN&gt;. Go through all of the following.&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Power options:&lt;/SPAN&gt;&lt;/P&gt;
&lt;OL&gt;
&lt;LI&gt;Go to &lt;STRONG&gt;Control Panel&lt;/STRONG&gt; (view by &lt;STRONG&gt;Large icons&lt;/STRONG&gt;) &amp;gt;&lt;STRONG&gt;&amp;nbsp;Power Options &amp;gt; Change plan settings&lt;/STRONG&gt; (of the active power plan) &amp;gt;&lt;STRONG&gt;&amp;nbsp;Change advanced power settings &amp;gt; USB settings &amp;gt; USB selective suspend setting&lt;/STRONG&gt;.&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Set both &lt;STRONG&gt;On battery&lt;/STRONG&gt; and &lt;STRONG&gt;Plugged in&lt;/STRONG&gt; to &lt;STRONG&gt;Disabled&lt;/STRONG&gt;.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;/OL&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="Niina_P_5-1749725566523.png" style="width: 400px;"&gt;&lt;img src="https://community.sinch.com/t5/image/serverpage/image-id/6573iD2346B97DF69296C/image-size/medium?v=v2&amp;amp;px=400" role="button" title="Niina_P_5-1749725566523.png" alt="Niina_P_5-1749725566523.png" /&gt;&lt;/span&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Device Manager:&lt;/SPAN&gt;&lt;/P&gt;
&lt;OL&gt;
&lt;LI&gt;&lt;SPAN&gt;Go to &lt;STRONG&gt;Control Panel&lt;/STRONG&gt; (view by: &lt;STRONG&gt;Large icons&lt;/STRONG&gt;) &amp;gt;&lt;STRONG&gt;&amp;nbsp;Device Manager &amp;gt; Universal Serial Bus controllers&lt;/STRONG&gt;.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;LI&gt;Edit the properties of each controller with “Hub” in the title.&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Select the &lt;STRONG&gt;Power Management&lt;/STRONG&gt; tab.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Deselect&lt;/SPAN&gt; &lt;STRONG&gt;Allow the computer to turn off this device to save power&lt;/STRONG&gt;.&lt;/LI&gt;
&lt;/OL&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="Niina_P_0-1749726271871.png" style="width: 400px;"&gt;&lt;img src="https://community.sinch.com/t5/image/serverpage/image-id/6580i623D4536F92B1540/image-size/medium?v=v2&amp;amp;px=400" role="button" title="Niina_P_0-1749726271871.png" alt="Niina_P_0-1749726271871.png" /&gt;&lt;/span&gt;&lt;/P&gt;
&lt;H2&gt;&amp;nbsp;&lt;/H2&gt;
&lt;H2&gt;Install headset manufacturer-specific drivers and firmware&lt;/H2&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;The &lt;STRONG&gt;Brands&lt;/STRONG&gt; selection in Communication Panel audio settings can cause problems if the manufacturer-specific headset drivers and firmware are not installed.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="Niina_P_2-1749723964481.png" style="width: 400px;"&gt;&lt;img src="https://community.sinch.com/t5/image/serverpage/image-id/6569i5A872290FB51F602/image-size/medium?v=v2&amp;amp;px=400" role="button" title="Niina_P_2-1749723964481.png" alt="Niina_P_2-1749723964481.png" /&gt;&lt;/span&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;Make sure that drivers and firmware have been installed before selecting the brand in Communication Panel audio settings. If the drivers and firmware have not been installed, select &lt;STRONG&gt;Other Brand&lt;/STRONG&gt;. Otherwise, the integration may not work as expected and it can cause various other problems.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;You can find more information about prerequisites for different brands in &lt;A href="https://docs.cc.sinch.com/cloud/operation-guide/en/oxy_ex-1/common/headsets.html" target="_blank" rel="noopener"&gt;the Operation Guide document&lt;/A&gt;.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H2&gt;Ensure the browser has permission to use the microphone&lt;/H2&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;Windows 11 has tightened app permission handling for microphones. On first use, the system may delay or block microphone access.&amp;nbsp;&lt;/SPAN&gt;&lt;SPAN&gt;This can cause the first call to have no outbound audio (agent can’t be heard). Audio works after the first conversation. &lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;Ensure that the browser has permission to use the microphone:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Chrome: &lt;STRONG&gt;Settings &amp;gt; Privacy and security &amp;gt; Site settings &amp;gt; Microphone&lt;/STRONG&gt;&lt;/LI&gt;
&lt;LI&gt;Edge: &lt;STRONG&gt;Settings &amp;gt; Cookies and site permissions &amp;gt; All permissions &amp;gt; Microphone&lt;/STRONG&gt;&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/P&gt;
&lt;P&gt;&lt;SPAN&gt;We also recommend agents to:&lt;/SPAN&gt;&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;&lt;SPAN&gt;Close Communication Panel at the end of each workday.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;LI&gt;&lt;SPAN&gt;Test audio by placing a test call after a Windows reboot or recovering from sleep mode.&lt;/SPAN&gt;&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H2&gt;In on-premise environments: check the following in your infrastructure in addition to the workstation settings&lt;/H2&gt;
&lt;H3&gt;&amp;nbsp;&lt;/H3&gt;
&lt;H3&gt;NAT binding timeout (UDP media ports)&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;NAT/firewall closes UDP port bindings during idle periods (for example overnight). In the first call of the day, the RTP stream is sent to a now invalid NAT mapping, resulting in one-way or no audio.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;To fix this:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Enable RTP keep-alive on the AudioCodes SBC and/or SIP endpoints.&lt;/LI&gt;
&lt;LI&gt;Configure frequent enough NAT binding refreshes (for example, every 15-30 seconds).&lt;/LI&gt;
&lt;LI&gt;Use symmetric RTP if supported.&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;Codec mismatch or delayed negotiation&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;Codec negotiation failure or delay in SDP exchange on the first call may cause missing audio.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;To fix this:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Verify codec priorities and make sure common codecs (for example, G.711 and Opus) are aligned across systems.&lt;/LI&gt;
&lt;LI&gt;Make sure there's no asymmetric codec handling on the first session.&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;SBC media session not properly initialized&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;The first media path may not get properly opened due to the SBC being in a dormant or idle state, or media anchoring not being fully active.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;To fix this:&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Check if media-anchoring or early media support is properly configured.&lt;/LI&gt;
&lt;LI&gt;Enable media timeout settings or pre-establishment of RTP on the SBC.&lt;/LI&gt;
&lt;LI&gt;Ensure ICE/STUN/TURN is used if endpoints are WebRTC-based or behind NAT.&lt;/LI&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;Ensure that the latest firmware is installed on the SBC&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;P&gt;It is always a good practice to keep SBC firmware as up to date as possible.&lt;/P&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;H3&gt;General diagnostic steps to investigate the issue&lt;/H3&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;
&lt;UL&gt;
&lt;LI&gt;Check SBC syslog and trace files for the first call SIP and RTP behavior.&lt;/LI&gt;
&lt;LI&gt;Use tools like Wireshark or SBC's built-in trace tools to verify:&lt;/LI&gt;
&lt;UL class="lia-list-style-type-circle"&gt;
&lt;LI&gt;SDP negotiation&lt;/LI&gt;
&lt;LI&gt;RTP stream establishment&lt;/LI&gt;
&lt;LI&gt;NAT behavior&lt;/LI&gt;
&lt;/UL&gt;
&lt;/UL&gt;
&lt;P&gt;&amp;nbsp;&lt;/P&gt;</description>
      <pubDate>Thu, 12 Jun 2025 13:16:52 GMT</pubDate>
      <guid>https://community.sinch.com/t5/Contact-Pro/Audio-issues-with-Communication-Panel/m-p/18448#M578</guid>
      <dc:creator>Niina_P</dc:creator>
      <dc:date>2025-06-12T13:16:52Z</dc:date>
    </item>
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