I have a Novatel MiFi4510L in a 4G area. I have found that about every 30 minutes web/ftp traffic stops being transmitted, but Outlook can still send/receive email to an Exchange server.
I end up logging into the device, clicking disconnect, then clicking connect, and all works again for about 30 minutes.
I've had a support case open with Verizon for over 4 weeks now, and they have not called me once to troubleshoot. I've received a few calls that have said they found the issue and it should be working now - it wasn't though.
I am so frustrated I can't even begin to describe it. I can't believe they haven't contacted me to replace it, or at least try or check configuration settings!
--Kent