Outlook 2010 and TLS issues – 0x800CCCDA IMAP_UNRECOGNIZED_RESP

Lately I’ve heard some people complaining about their Outlook no longer wanting to receive mail. All of them use the same settings for mail, so there should be something there that is causing issues:

  • Mail client: Microsoft Office Outlook 2010
  • Account type: IMAP
  • Secured connection: yes, TLS
  • Error code: 0x800CCCDA

So far, a quick look through Google doesn’t give any useful results. In addition to that, the Microsoft support pages don’t give any hits on the error code provided by Outlook.

So far I haven’t been able to reproduce these errors, I’m suspecting the av software used by the clients, but haven’t been able to pinpoint that. If anybody has a clue on what causes this error, please let me know :)

About Pieter

Currently working as a WordPress Support engineer at a Dutch hosting company. Actively submitting documentation for WordPress and sometimes helping out with WordPress Core development.