Mysterious Windows Mobile - Exchange ActiveSync error code

Today I got a new error code I've never seen before while trying to sync a WM5 device to Exchange... 0x8600020B ... never seen it before and believe it or not, Google has no hits either.

Managed to get the bottom of it and I'll I'm going to say is: forget the handset, go check the server. The application event logs on the server in particular. I'm guessing this condition could be caused by multiple root causes leading to the same symptom... in this case it was disk space on the server running critically low, leading to IIS issues amongst others.

And as always, when troubleshooting EAS, always check OMA - it'll always point in the right direction...