Chosen Solution
Reset network settings, replaced the antenna as well as the flex cable. It seems to work only for a short time – when I reseat the SIM card and reset the network settings. It then goes to SEARCHING… then NO SERVICE and then back to the provider network. I did review other similar questions. Could it be the SIM card or connectors in that area?
These symptoms usually lead into a rabbit hole. While it is searching/No service, input *#06# into the keypad and see if it brings up your IMEI number. If it doesn’t you have baseband problems. The other thing you can check is the bottom antenna it is located beside the charge port connector or is that the one you already replaced?
I’ve seen that problem before. even if you replace the correct part. usually it will work temporarily but after a while the problem will come back. I speak from experience that this is not easy or impossible to make
