You have to look at your wireless plan if it includes "short text code" this will allow you to receive text messages from short numbers.
Did you check the network if your plan supports short codes?
check if the phone has scam protection On.
I have issues receiving or sending messages from certain people. I went to AT&T and all they could tell me was delete the entire conversation, delete your contact and try again. Really, I didnt have this issue with the Note 8.
@Samsung_V69u1NP can you check the 'message center number' if it's correct? it should be there on the settings on the stock messaging app. compare the number to at&t website.
My issue to receive third party texts has not been resolved. I have gone to the Samsung authorized center to get this fix and was told it is a Verizon issue which I am convinced is the case but they don't know how to fix it, talking about waiting for a security patch to come out in about a month ..and maybe that will fix it, have you heard of a fix? I shouldn't have to wait a month. Anybody else experiencing this issue on an unlocked S10+?
@userEJRGQ7FhNC Try to use google messages app and see if it helps solve the problem?