@Romel Patell
Thank you for your post and I apologize for the delayed response!
Based off your error message - PublisherDomainMismatch, and as you stated, this occurs when neither the app's Publisher Domain nor one of the custom domains added to the Azure AD tenant match the domain used to perform email verification in Partner Center.
As of right now, there aren't any workaround to override this pre-requisite of Publisher verification - the email address used during MPN account verification must either match the publisher domain configured on the app or a DNS-verified custom domain added to the Azure AD tenant
. For more info.
If you have any other questions, please let me know.
Thank you for your time and patience throughout this issue.
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