Outlook for Mac 2011 cannot recieve mail. “error code – 3253 “connection to the server failed or was dropped”

Hi

I'm writing on behalf of someone else.

We're unable to receive mail. Get this message immediately: error code - 3253 "connection to the server failed or was dropped"

What we have tried:
Verified that the same setup works in Mac Mail (Port 995 and 110, with or without SSL)

This only occurs on POP connections. Not IMAP or SMTP

Same error on different account on the POP server

Rebuild the database does not help

Same error when setting up an entirely new database.

Some symtoms similar to this bug: http://www.office.mvps.org/error/number.html#error_3253

The inbox was initially 2500 mail, but after moving half of them to an archive folder, and rebuilding the database, the error persists.

The "Sendt items" folder contains a lot less than 2500 mail

So as far as I can tell, this is not the same bug:

Made a new user profile on the mac. This worked until we imported the original database (11Gb).

Reinstall Office completely with update after this instructions did not help: https://support.microsoft.com/en-us/kb/2398768

OSx Yosemite. Latest update as of 8.05.2015 (don't have the Mac here now, and can't remember the version number)

Latest version of Office for Mac 2011 as of 08.05.2015 (don't have the Mac here now, and can't remember the version number)

I have no idea what to try next. Any help is appreciated :)