@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. 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