Switching a SIM card to a new phone

[strider21]

I have just bought a Galaxy S23 & switched my existing EE Sim from an old Galaxy phone.  All ok except I cannot access phone network. I get a message saying "Not registered on the Network". How do I solve this? 

[Leanne_T]

Hi there @strider21 

Thanks for coming to the community. 

Does the SIM card work in the old device? 

Did you receive a new SIM card with the Samsung? 

Leanne 🙂

[bristolian]

A replacement SIM is often supplied with upgrade phones incase, for whatever reason, there's a problem with your current SIM or it doesn't fit a new phone.

If your existing SIM is working and fits your new phone, there's no need to unnecessarily replace it.