Update your MX records to transition to the global Exchange Online service
Sign in to Microsoft 365 admin center, and go to Settings > Domains
Status will be shown on the right side for each domain. If your organization’s domains point to Microsoft Cloud Germany Exchange Online, you'll need to update your MX record.
Click the domain, then click DNS errors detected, click here to view.
This page will have instructions to show you how to fix the MX record. If your domain’s registrar uses Domain Connect, you can click “Fix my records” on top. Otherwise you can follow the link in the wizard to step-by-step instructions for your registrar.