Hello @RogerSchlueter-7899
Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.
Can you please check whether the email address is populated in Azure Active Directory > Users . If in case the email address is not populated then user need to be added as a Guest user.
- Login to the Azure portal using an account that has the necessary permissions to add external users.
- Microsoft Entra > Users > New guest user.
- Invite the user to the tenant "Microsoft Services"
- Accept the invitation.
Now login again and try to create database, if the issue still persists then let us know
Thanks,
Aditya