It looks like you might be posting about buying/upgrading/trade-in or comparisons between models, in which case you should comment in the pinned WSIB thread. If your post isn't about any of the above topics it will be approved shortly - there is no need to message the mods.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

I would remove the sim, and clean it with a dry microfiber cloth and re-insert it. Also try restarting the phone after reinserting it. Just rub the metal contacts on the SIM card until the dull metal looks shiny again. It may just not be making good electrical contact. Don't put any water or liquids on it, just use a dry microfiber cloth to clean it. If this doesn't work, the SIM card could be damaged, or the phone could have hardware damage. Do you have another SIM card to test with your phone. If the SIM card is damaged, you can get a new one replaced from your cellular provider.

Call carrier upgrade sim

I had a similar problem back in the days. A new sim card fixed it for me.

Say simsalabim 3 times

Post on Reddit!!!!

How about calling Apple or your provider?