I have two Samsung phones, one is a Galaxy S III and the other the Rugby Smart. They are both AT&T locked and I have AT&T SIMs. The data and MMS work intermittently.
Most of the time, when I try to browse a web page, it either say "Webpage not available" or the page loads but some of the pictures or label don't come in.
I do see the 4G icon on the status bar but the access is very flaky.
I have all the APN/MMS settings. I have set the APN type correctly. I even split the data and mms into to different APNs. Nothing fixes the problem.
Hopefully someone can help.