iMessage error in activation.
So recently I got a new phone number and my main way of messaging people is iMessage, anytime I try to connect them it says error. I have waited over 24 hours since I put in my sim for it to activate on its own but even that isn't working. I signed out of my Apple ID and signed back in, removed the sim and put it back in, checked I had all the right settings and newest updates, turned iMessage on and off, restarted my phone and checked all of the relevant settings again. I am lost and Would please like help. PLEASE. Thank you
iPhone 12, iOS 15