Sim card won't send sms, tested on 2 android devices

My wife's oneplus 7 pro the last 2 days won't send texts but receives messages ok. All other network related functions work fine, no sim card errors, etc. Tried all kinds of things to get working.

I swapped my sim with hers. Using her device with my sim card, sending text msgs works. Her sim card in my S21 Ultra however, I get the same issue, no outgoing texts.

So in my mind it's a sim card issue, not device related. It's just weird that only sms seemingly affected. Any ideas??