Debugging ActiveSync for devices having problems accessing Exchange

In order to debug activesync problems with devices such as mobile phones, tablets and so on you will firstly have to enable ActiveSync logging on the user mailbox (as this is not enabled by default):

Set-CasMailbox –ActiveSyncDebugLogging $true –Identity <mailbox-name>

You can then retrieve the logs manually using the Exchange Shell:
Get-ActiveSyncDeviceStatistics –mailbox <mailbox-name> -GetMailboxLog:$true –NotificationEmailAddress <user-email>

The above command grabs the current statistics and activesync log and sends them to a specific email address.

Finally we can turn of activesync debugging:
Set-CasMailbox –ActiveSyncDebugLogging $false –Identity <mailbox-name>