Hi,I had the same error on my system (Debian 11.6). It seems like the imapd process runs as the normal user after login. Hence the shared directory needs to be readable and listable for those:
$ chmod o+xr /etc/courier/shared did the trick and then on my system working permissions are: $ ls -ld /etc/courier/shared/ drwxr-xr-x 2 root courier 4096 May 17 2016 /etc/courier/shared/ Best, Markus
