We updated our license files (April 8) and recently noticed that we were not receiving e-mail notifications. I stopped DISPMAN and tried to start again but it fails immediately. Looking at the event history I see this error:
Failed to start DISPMAN configuration INVALID CONFIGURATION ENTRY PERSON The configuration entry is invalid due to licensing restrictions.
I compared to our other systems and do not receive any errors. Also, the license shows as valid until 03-31-2022 which is what I would expect to see.
It sounds like you have the same license across all servers. This is good. And DISPMAN configs start fine on the other servers means that it should not be a license issue. Check if there is anything looks quirky in the DISPMAN config, particularly in the PERSON entries. Note default PERSON entries look like this / have this format and syntax:
PERSON ( EmailAdmin, MAIL, DefaultEmailService, "email@example.com" ) PERSON ( IRKnowGrp, MAIL, DefaultEmailService, "Knowledge.Group@ir.com" )