GDLHB

[GDLHB]

Hi there my S21 fe won't recognise my sim card but my old phone an S8 will has anyone had same issue and if so what was it and how did you fix it 

Thank you 

Kind regards GB

[Robot-]

Some phone just don't like old sims and require them to be replaced.

[Glenntech]

As @Robot has mentioned.
You will probably need a new sim card.
That's assuming the phone you have isn't locked to a network provider.
I've had a similar problem with my old sim cards and new ones fixed the problem.
See also if your network provider can push settings to your phone

[GDLHB]

Cheers for that 👍

[Bigtasty65]

Give it time maybe?
I've just bought the S22 5G and it didn't recognise the network of my main SIM in the 1st slot. It did recognise the network of the 2nd SIM card for some reason. All of a sudden, when I went to SIM card manager it recognised it!
Give it time perhaps??
👍🏻