This is a new installation but a bit panic anyway since some users have start to use it.
One AD Server (win 2019) and one Exchange server (win 2019 and Exchange 2019).
Pretty standard installation of everything.
Incoming email are working fine.
Sending email is not working at all.Nor internal or external. Not even if I send to myself.
First I thought that the send connector to a smart host was failing but there are nothing in the logs, and since all internal messages are failing as well, it must be something else.
DNS settings points only to AD Server. Nslookup from Exchange server works fine. OWA works fine.
Certificates installed by best practice and seem to work quite well.
In Outlook client the sent messages are going to the sent folder. In OWA they go to draft with message "Something went wrong and we have not been able to send your message yet".
Tell me where to start looking and I will give you all the details needed.