This just happened to me the other day, not initiated by anything I did. It started with my iPhone “acting” weird (smartphones be acting stupid!) telling me that No SIM was installed, which was bullcrap (in my experience, phones start “acting” this way at the 1.5 to 2 year mark... Hmm I wonder why?? Planned Obsolescence perhaps???).
Anyway, when I saw that message, I restarted my iPhone, and it was functional. However, I didn’t notice until later that my iPad could no longer send or receive my SMS messages (iMessage was fine).
I did some basic troubleshooting.
I went to Settings > Messages > Text Message Forwarding
- Disabled and reenabled the iPad (and got no Forwarding code on the iPad)
- Turned off/on iMessage on iPad
- Rebooted iPhone and iPad throughout all this in many different combinations (while sometimes leaving things off before restarting, and reenabling them after reboot, etc.)
None of that worked.
Today, I searched online for an answer again, and it led me to this post, for which I’m grateful, because it led me to investigate my settings once more, and I stumbled upon the problem and this is what fixed it for me!
Settings > Messages > Send & Receive
I don’t remember what the settings were on my iPad before this “broke” a couple of days ago, but when I got into my iPad settings, I could see that my phone number was not set to “Start New Conversations” which made me think that was the problem, so I compared the settings to my iPhone and ensured that my iPad was matching the iPhone settings. I specifically have both set to “Start New Conversations” with my phone number, and I think that’s what did it!
Note that this fixed things right away, no need to reenable or resend codes or anything.
I hope that helps someone!