@SeppyUV

Locate the file vendor->uvdesk->core-framework->Services->EmailService.php.

Open the EmailService.php reach to sendMail() function.

and dump() the exception as in attached images.

4c9f3aa9-c88e-4350-8b67-5e7d2dd7c268-image.png

5f7f7fe9-147f-4329-91f0-1f41f03c5d54-image.png

It will show the error you are facing while sending mails (if adding an agent, creating a ticket etc).

Other helpful link:
https://forums.uvdesk.com/topic/1870/how-to-debug-the-error