I recently upgrade my phone to Android 7.1.2 and, after 2 days running quite smoothly, yesterday my phone switched to 2G and I don’t have any chance to select 3g nor 4G. The “prefered network” option is in grey color and I cannot do anything to try to use better connexion.
I’m only using one SIM card (I know that is is a common issue when using 2 SIM cards).
I tried to reboot, I tried to use the othe SIM slot, I tried to use another operator, I enabled disabled the network, etc…
What else can I do? can it be a SIM problem? anyway to make sure that it’s a SIM before going to the shop and order another one? (it costs 5 or 10€ and I don’t want to spend that money if it’s not going to fix the problem).