Mail issue with IPhone and Rogers

[VE3YYZ]

Have a friend with an interesting issue with his IPhone.

The phone is an IPhone 4 with the recent iOS. His carrier is AT&T, (has three companies, one in the States, hence the US phone, which even with the roaming is cheaper than any Canadian provider).

He is accessing two accounts via exchange server, one personal corporate, the other general corporate. The mail server is hosted at Google. Lets call the personal joe@xyz.com, the other sales@xyz.com. Both accounts are IMAP.

The issue is intermittent, with the mail server on only the joe account giving errors. The sales account does not display these issues. Both accounts are set up exactly the same. It also only appears when accessing the server via Rogers. Does not happen when accessing via a hotspot. When it does occur, the sales account still works. I let him borrow my IPad, which is on Bell, it didn't display the error, while the phone did. All the other Google business apps work fine on the phone.

Only solution is to power off and on phone, then it will work, but it is annoying. Will work for a few hours, or days or weeks, then the issue reappears.

Have contacted both Google and Apple. Apple gave the typical non answer, while Google ran some tests and felt they where running okay. Contacted another friend, who works with Rogers, he didn't think it was a network issue.

My friend's business is completely Apple, none of the other devices display this issue.

Anyone have any ideas?