After Migration Exchange 2007 to 2013. Exchange 2007 user automatic connected with Exchange by using activesync and after migration mailbox 2007 to 2013. Now 2013 mailbox user few connected and few not. As like 1 GB mailbox connected but not sync inbox empty. I can't understand what i can

Hi Ramin

Please check the following things

Check your activesync policy properties
Ensure the affected device has appropriate network connectivity, their Active Directory account is not locked, the password is correct, the password has not expired.
Use https://www.testexchangeconnectivity.com/ to rule out any issues with the ID or the environment in case the issue isn't with the mobile.
Remove the account on the phone and re-create it to see if it will synchronize mail. 
Try using your domain\username rather than just your username when setting up the ID on the account
Try  using the server name rather than the web URL in the account settings.