Problems with the new Outlook and Exchange Server 2019

Hello everyone,

I wanted to ask if anyone else has this error with the new Outlook.

My main email address runs on a German Exchange 2019 server. The domain is secured with Let’s Encrypt SSL. The MX entry in my DNS settings is:

mail-gateway.ip-projects.de

In Outlook Classic everything works without any problems and error messages. Only the new Outlook can not connect.

It’s not a problem, because the classic Outlook will run until 2029. But I still find it a bit strange. Thanks.

Christian