I have exchange 2010 server, 2 CAS, 2 HUB and 2 MBX servers. I have a problem sending mail through mobile. Normal text mails are going with out any issue usning any monile. But if we attach any attachments more than 50Kb, then mails won't go with msg "Failed to send" Max from all monies this is issue, expect some black berry mobiles.
What might be the issue?