In the last day or so I've started to find customers with Outlook or Outlook Express being unable to collect their email. The error they get is "connection closed by foreign host".

I find I can log on to their POP box with Eudora and clear the queue. Sometimes Eudora also throws up the same error message - but unlike Outlook, it behaves well and can resume downloading the rest of the email queue.

Obviously a solution is for them to change to Eudora - but folks seem to just like to stick to their Microsoft software!

I suspect there is some particular spam or virus out there that is tripping up either QMail or the email client software and causing this problem.

I wonder - is anyone else experiencing this problem?

telnet yourserverip 25
telnet yourserverip 110
If both of these work than the server is ok. Check with your clients for antivirus software that replace your server with an antivirus "forwarding server".

Also have those customers log into Webmail, or do it yourself if you have their email password info. Look for any emails that have a non-breaking space character in the From: field. Delete and purge those via Webmail and you'll like find that everything starts working again.

Don't ask me why Outlook is choking on those totally blank emails, but I've had a couple of clients who use Outlook unable to retrieve all of their email. Once these totally blank emails are deleted and purged via Webmail they're fine again.

Thanks Squire. I think webmail is the answer. I had been put off Plesk webmail by a post I read somewhere claiming that it didn't really work too well.

However it seems to be just fine so far! (and that's on my ancient Plesk 5)

For me, the real problem with Outlook is not so much that it can choke on an email in the way you describe - My Eudora does that too sometimes (possibly for the same invalid characters in the email address). But Eudora seems to just carry on from where it left off, whereas Outlook is too dumb and just keeps re-trying from the queue start.

And the message folks receive always suggests that the problem is caused by the mail server...