This was posted by someone and it actually worked.
•Confirm cellular data is enabled by going to Settings > Cellular > Cellular Data
•Try turning Airplane mode on and off again by going to Settings > Airplane Mode
•Go to Settings > General > Restrictions > Cellular Data Use, make sure “Don’t Allow Changes” is toggled off, then tap Settings > Cellular, then turn Cellular Data to OFF, wait a few seconds, then turn Cellular Data back to ON
•Reset Network Settings by going to Settings > General > Reset > Reset Network Settings