Samsung Galaxy Xcover2 - no ActiveSync email over cell network

Really strange problem; my user's Xcover2 works fine over wifi, but when out of range and depending on the cellular 3G (or 2G) signal, can't receive any email from my Exchange server. At these times, it has internet access, can access a Gmail account etc and other handsets on my system (iPhone, Nexus 4, iPad, HTC Desire etc) never have any problems.

Could it be a problem with the handset itself?

thanks for any help,

Calum

via Smartphones: PinStack.com http://forums.pinstack.com/f324/samsung_galaxy_xcover2_activesync_email_cell_network-140615/