Accepted CCS invitations deferred: Permission denied: failed to chdir to /opt/cpanel-ccs

Symptoms

The server doesn't send a response when a calendar invite is accepted, and an entry similar to the following can be seen in the Exim main log.

2024-04-24 18:28:47 1rzgQK-008wiJ-24 == cpanel-ccs@server.domain.tld R=localuser T=dovecot_delivery defer (13): Permission denied: failed to chdir to /opt/cpanel-ccs

Description

This issue occurs on CloudLinux servers with CageFS when the cpanel-ccs-calendarserver package has not been added to CageFS.

Workaround

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
2. Add the cpanel-ccs-calendarserver package to CageFS.

   cagefsctl --addrpm cpanel-ccs-calendarserver

3. Remount and update CageFS

   cagefsctl -M

   cagefsctl --force-update

4. Reset the permissions on the cpanel-ccs-calendarserver files.

   rpm  --setugids cpanel-ccs-calendarserver

Additional rescources

How to add a command or binary to CageFS for all users using addrpm

How to clear the Exim retry database