A few of our users noticed that it will stop working intermittently for them. I didn't believe it at first until I changed my android phone and it started occuring for me. It will just stop syncing completely, it looks like the server is blocking the device completely. This mainly occurs when they are using the wifi.

I've done some testing. If I switch off the wifi and use the phone data plan it will work fine. When it's on the wifi network, I try and browse to the webmail/owa page and it says page not found! I did a dns lookup and they resolve correctly. If I use another device on the same wifi network, it can access the exchange servers fine. Sometimes the wifi network will just work without any issues. But when it fails, it looks like the phone constantly checks the server every second to see if it is online even though I've got it on manual sync. I was wondering whether it tries to sync too many times and exchange thinks its a denial service attack.

My old android phone that works is Froyo and the new one is Icecream. People who have reported issues seems to be newer phones. They also tested their own wifi network at home and experience the same problem.

We haven't patch our exchange recently before seeing this problem.

Anyone has seen this issue?