Although it is technically possible, we strongly recommend not to use the corporate domain to send marketing emails. It is always better to use a new domain to send marketing e-mails. The benefits are:
Lastly, in our experience corporate domains are managed by the Corporate IT team and they do not allow internal teams to use the corporate domain for marketing email because of the above issues.
We can procure a new domain for your marketing emails use case. Refer to the E-Mail 365 API Specification for more information.