I access the account with no problems using activesync on iOS and a browser at outlook.com, however I tried to set up IMAP access using Mail.app on Mac OS X today and it fails to authenticate. I used the same settings with an @live.co.uk email account and that works fine, which leads me to believe the problem is to do with the fact that I am using a custom domain.

I've seen some other similar threads which indicate that there have been problems with custom domains and IMAP and wonder if Microsoft are aware of this issue?

Thanks.