TLDR: if you don't get some multi-factor auth codes via text message, call Verizon and speak to tech support. They may need to update your phone while/after you reset the network settings.
I have finally solved a problem I was having with receiving 2FA/MFA codes from short code providers and I wanted to share my solution in case it could help someone else. Short code providers have numbers that are only a few digits long, like 89986, rather than a full phone number. When I would request an MFA code for some websites, these messages either never came through or would come through *hours* later, which made them useless.
This problem only started after recently switching to a 5G plan on my iPhone 15. I'm currently on iOS 18.5, but have experienced this problem for the last several months on older iOS versions, too.
I scheduled a call back from customer support through the Verizon app. I asked to speak to tech support and the person calling said I was in the right spot. They said I should reset my network settings--which I'd done before, so I was skeptical. However, the key point he made was that I had to do this *while* he pushed an update to my phone. So, while on the phone, I did the Reset Network Settings operation in iOS, which disconnected our call. He called me back after the phone restarted. I tested out 2 websites to see if short code MFA messages would come through and surprisingly, it worked! The messages came in immediately, instead of being stuck somewhere for hours.
I wish this was something I could resolve on my own, but glad it finally got fixed and didn't take hours on hold with customer support.
