Ok another thought. The general ip address used on a cell phone are ( can be ) static and in most cases works without any issues. such as 192.168.1.71. If the router has issues with the address it will connect but not allow data to flow. It might help to check and if in static mode switch to DHCP mode. This will allow the phone to ask for an address that's available.
APN issues without a carrier data service
the other issue could be the APN used on the phone. The explanation is long so I listed a link to show the steps to change or check.
This is ATT stuff so check with your carrier if different.