Thanks for the reply,
I went through the troubleshooting methods then called the carrier, they told me it was an issue with the phone and that I had to contact the manufacturer. I uninstalled then re-installed grapheneos on the phone, and haven't gotten the error so far. Worst comes to worst I'll just try again with a new sim card.
Thanks again for the reply, I was really worrying I was missing something obvious when I was trying to sort it all out.