on 04-08-2024 18:04
Hello. I just got back from a month long holiday and I don't have a signal on my phone when I landed in the UK. It says no sim available. I've tried everything from restarting phone, reinserting sim and resetting network settings and none have worked. But when I inserted my sim on my mum's phone, there is a signal and is working fine.
on 04-08-2024 18:47
Suspect a phone issue then.
You can get it confirmed in any O2 store or by checking with your phone manufacturer.