I also got SOGo to work with the sieve service, my mail data resides inside a firewall. I had configured the port forward correctly, my problem was the sieve socket was only accessible by the local machine. I changed the cyrus configuration for:
sieve cmd="timsieved" listen="sieve" prefork=0
Note: the above command also changes the port that sieve listens from 2000 to 4190, you can find the port list in /etc/services
I am attempting to retrieve email from a gmail account using imapsync, IMAP access is enabled in the gmail account but I think the problem is happening before the gmail IMAP service access, sounds like a network topology problem?