takin2225 We had to make a similar change for our Dynamics GP on premise environment.
What‘s required to change authentication, is setup Application Oauth configuration in Azure Enterprise Applications that you will input during setup of the Dynamics email configuration. There should be an option to set an APP ID for modern auth.
When setup users will authenticate using their Microsoft O365/Azure login via SSO using Oauth 2.0.
Search in the Dynamics GP technet or app development communities for Modem Authentication, you will come across support articles explaining how to configure for particular version of Dynamics GP you have.
It’s a very quick and easy process to do.
Good Luck!!