Mac Sonoma 14.2.1 can't connect to internet
My desktop computer Apple M1 with Mac Sonoma 14.2.1 can't connect to the internet. I'd downloaded the newest version of Firefox, don't know if that had anything to do with it but I haven't been able to connect since. Laptop and phone aren't affected, it's just the desktop. Are there any settings I can try changing before having to deal with AT&T?
Help appreciated! Thanks.
iMac 24″, macOS 14.2