att network via sim card will not connect to chromebook
***THIS IS NOT A WI-FI CONNECTION ISSUE***!!! I have a chromebook OS that I purchased on May 22nd. I have the $20 a month data plan on the line. When I insert my sim card into the side of the chromebook and select ATT under network, it tries to connect and but then i get the following error codes: 1. Modem not registered 2. org.chromium.flimflam.error.failure. NOBODY has been able to assist me with this issue from tech support to live in person reps. We have done every type of reset option known to man and we have replaced the sim card as well. If ANYONE can help me out I would greatly appreciate it!!!