Whenever I add another account to Thunderbird, I have to specify that it can only have one connection to the server per account and even then, if my wife switches on her machine, we have more than the prespecified Plesk maximum of 4 IMAP connections and we start getting errors.
I devided that enough was enough and went in search of a solution. I found it too :o)
perl -p -i -e 's/^MAXDAEMONS=40/MAXDAEMONS=80/g' /etc/courier-imap/imapdThen a quick restart of the service and all should be working.
perl -p -i -e 's/^MAXPERIP=4/MAXPERIP=40/g' /etc/courier-imap/imapd
/etc/init.d/courier-imap stopThese changes increase the maximum daemons to 80 and Maximum connections per IP to 40. Should be enought for us at the momnet, but may need altered in the future.