I need some help because I'm not able to resolve this case.
I got a MS Exchange 2010 and some mobile device (about 15-20 iOS/Android/WPhone).
It's impossible to send an email with those device with more than about 600-700kB of attachments.
I got a message on the device "failed to send" or something like this.
I've activate the activesync logs in ECP but nothing relevant. Nothing MS logs.
No problem with outlook client.