Hello everyone
I have a pixel 7a with Graphene OS which i was using with a Esim but i decided to change to a sim card but now i'm not able to receive or make calls with it. I have added APN settings of the sim card and i have internet data i can send and receive SMS. I deleted the previous esim.

    sandking414 does your phone app have all relevant permissions granted for its functioning?

    sandking414 you could check if there's some misconfiguration. Maybe the registration failed, but you can check that too.
    In your dialer app, enter the following:

    *#*#4636#*#*

    There you'll end up in a test menu. The first entry (should say something like phone information) lists all the necessary details. In the upper right corner is a three-dot menu. There should be an entry for "IMS status" (or similar). Does it say: "registered"? Is Voice-over-LTE or Voice-over-WLAN available for you?