Network Mode / 4G

[fidom]

Again I am posting this here as there does not seem to be a mobile phone forum. I am British but living in Croatia. I still have a property and income from UK. I have a Samsung A50 phone which I bought secondhand. I'm not sure if it is related to the current problem but a few months ago I did a factory reset. It is dual sim and I have UK Giffgaff and Croatia Simpa sim cards. When I try to make a call on the UK sim I get "Not registered on network". On the Croatia card the call works. I can receive text messages on the UK sim and I topped it up so I know there is credit.
I watched a YouTube video about the problem and it was suggested I needed the network mode set to "LTE/4G/3G/2G (auto connect). On my phone I could not find a menu option that includes 4G so I had to set it to LTE/3G/2G (auto connect). As it is set like that for both sim cards and it works on the Simpa sim I don't suppose it is the problem but am I missing out if I can't access 4G?

 

[Wayners]

You need to make a chargeable text or call on giff gaff once every 6 months to keep it active I think. Have you done that?

LTE is 4g.

APN settings. I wonder if the giff gaff apn settings will automatically set when abroad as you carried out a factory reset? I think they do.
Also make sure roaming is switched on for giff gaff in the settings. With roaming switched on giff gaff should automatically pick the local provider

 

[fidom]

I resolved the problem by buying a new, cheap phone (€32.99) I actually topped up the phone to make sure it was still active (that works to activate it and I knew the call I needed to make would be expensive).