Cannot receive SMS messages

I know this is an FAQ, but I can’t see a clear answer.

I only use one app on my Pinephone and my memory is a bit hazy, but I feel like once upon a time it could intermittently receive SMS. That hasn’t been true for a long time though. I know that receiving SMS is a feature that was known to have serious problems, but I’m starting to find it suspicious that it doesn’t work at all, over years and many software updates.

I can make and receive calls to my iPhone (iMessage is disabled). I can send SMS to my iPhone, but I can’t receive SMS from the iPhone. If I swap the SIM cards between the two it’s the same.

Can someone tell me what the current state of receiving SMS is? Is it supposed to work? Is there a way to diagnose if something’s going wrong?

I can’t even figure out how to report my current software version. I updated recently, if that helps.

Probably the same issue as discussed here Modem Manager Poll - #8 by bogdancovaciu
With my provider i do not have such issues.

For the record I’m using T-Mobile in Germany. I have also experienced the same problem with Vodafone in Australia.

For me SMS has been working flawlessly for 2 years. Only MMS had problems until relatively recently.