[Dovecot] Filed to write auth token secret file

Hey guys, I am getting the following error. It seems not be be severe, since my setup works without any signs of drawbacks. But I'd rather rely on a professional opinion.

May 28 23:02:54 example dovecot: auth: Error: open(/var/run/dovecot/auth-token-secret.dat.tmp) failed: Permission denied May 28 23:02:54 example dovecot: auth: Error: Failed to write auth token secret file; returned tokens will be invalid once auth restarts

Thanks in advance Chris