IMAP accounts consistently offline

Question

This is more of an annoyance than anything. I have 3 IMAP accounts and they always, always show the caution triangle. Clicking on it gives me the Alert box with:
"The server error encountered was: The attempt to read data from the server "xxxxx.xxxxx.com" failed."
But I can send and receive email just fine. Wondering why this happens?

Answer 1

OK gang -- I have a solution to try for this.
The problem -- at least in my experience -- is using a Apple Mail program to access IMAP accounts served by PLESK.
The root of the problem is the number of simultaneous IMAP streams originating from a single IP address -- a problem if you have multiple IMAP account on one Mac or have a number of email users behind a router (sharing the same external IP address).
This problem is exasperated if an office buys iPhones for their staff -- as this double the number of IMAP streams in an office all hitting the PLESK served IMAP service.
Here's the fix:
1) Login to the Plesk server as root.
2) Change directory:
cd /usr/lib/courier-imap/etc/
3) Edit the imapd file (I use the emacs editor for this)
emacs imapd
4) Find the line that begins with set MAXPERIP=
5) Change that line to read set MAXPERIP=40 or set MAXPERIP=60 (or higher if needed). Mine is at 80 currently.
6) Stop and Start IMAP services:
/sbin/service courier-imap stop
/sbin/service courier-imap start
This fixed this issue for me. This fix works on PLESK 7.x.x.
NOTE: I'm in the middle of migrating to PLESK 8.2.1 -- and this fix can't be applied as written because the MAXPERIP parameter is set via a variable in 8.2.1: -maxperip=$MAXPERIP
If anyone knows where to set the $MAXPERIP variable onder PLESK 8.2.1 please let me know.
Hope this helps you!
scotto