I am facing the same problem, 2 things are for sure and the third almost looks like the cause.
1) Installation of latest patched and O/S update 2.01
2) Big sized mail with Attachments
3) Klez / corrupted e-mail header
The moment my box starts getting mails infected with klez the mailbox starts giving an Envelopes error and stops access via a client it would still work thru webmail.
I am close to a view that if you need to invite DOS attacks on yr RAQ you should install O/S update and wait for klez.
I have been given solutions like deteting the oldest mail which shall always have an attachment / klez whenever this problem occurs but it dont work for me cuz my Catch-All boxes get mails virtually every minute.
BTW has anyone used a good email filtering s/w for RAQ, suggestions would be lovely
I confuse with this problem...this happen in our both server : Raq3 & Raq4.
Typically happen on a USER with almost full qoute or have many emails inside (more than 5- emails) !... this happen on some website's clients...just several clients but make headache!
This is error when my cleint try to receive email via Outlook Express (using Webmail is no problem) :
"There was a problem logging onto your mail server. Your Password was
rejected. Account: 'mail.xxxx.com', Server: 'mail.xxxx.com',
Protocol: POP3, Server Response: '-ERR [SYS/TEMP] maillock error 3:
'/var/spool/mail/stk'', Port: 110, Secure(SSL): No, Server Error:
0x800CCC90, Error Number: 0x800CCC92"