Send Welcome email failed

[nicoonline]

I have created 2 users with Microsoft365 synchronization. The email address is correctly synchronized. I tried to send the welcome email but the email does not seem to be sent.

I have checked that it is not caught by our anti-spam and I have not seen any evidence of smtp calls.

How can I debug on the 3cx itself?

 

[nicoonline]

I have done some research and it seems an issue only on the M365 email address. If i change the email address manually it's working, it's very strange !

 

[Marconi]

See my response to your other post but you should also check that there are no invalid characters in the email address being synced from M365.