Apple ID phone number invalid

I’m having an issue with my Apple ID. I am trying to add my UK phone number but i get a “phone number is invalid” message. I’ve been using this number for years without issue. I have recently changed SIMs and there was an issue porting my number, O2 claimed it was complete but it turned out that I couldn’t receive SMS messages. I tried to add the number at that time, Apple sent the verification SMS but I didn’t get them. Could it be the case that my phone number has been blocked by Apple to cause this issue?