My younger brother's phone has mobile data, but whenever he goes out, the connection stops working. Restarting the phone brings data back for about 15 minutes before it fails again. The phone is updated, and this used to work normally. He'll be starting school soon, so I'd like to figure out how to fix it.
2 Answers
Since the phone is already updated, check the mobile network settings first. Make sure mobile data is enabled, the correct SIM is selected for data, and the preferred network type is set to 4G/5G automatic. You could also remove and reinsert the SIM card or reset the network settings.
A factory reset is worth considering if the problem continues, but back up photos and other important data first. Before doing that, test the SIM in another phone or try a different working SIM in his phone. That will help determine whether the issue is with the phone or the carrier/SIM.

It’s strange because the connection worked normally before, so I’ll test the SIM and network settings before resorting to a reset.