SIM showes "no service"

i came home from beeing in canada for half a year and now that im back to norway my simcard is not working. I tried it on another phone and then it works. I bought my phone in norway before i left and it was working before i left and when i was in canada.

I tried:

restarting the phone - did not work

i changed my sim card - did not work, but works in different iphones

reset all settings and content on the phone - did not work

I dont know what to do anymore :(

thanks for your help 😊