20 Jan 2022, 10:51

@mxdevito did you run the cron job as root?
php bin/console uvdesk:refresh-mailbox xxx@xxxx

Seems yes as I see administrator@ before the command line.
If you run the mail command as administrator you can get errors so again you need maybe to check if the dev folder is under admin or under normal user account group.

If you go under /uvdesk/var/cache/ by ssh than you run the following command:
ls -l dev

what do you see?

Seems you have server file or folder permission issue.
If you search on Google the error "could not be opened in append mode: failed to open stream: Permission denied" you will maybe see what can be wrong.