Not Receiving Certain Group Texts

Hello,

I have been having issues where I am not receiving a group messages from certain people. I am in quite a few group chats and have been receiving those fine, but there is one that I just don't receive. Yesterday, I got group messages that had been sent the day before which was odd. My Iphone software is up to date. I have restarted my phone multiple times, reset network settings, logged out and in to my Apple ID and nothing seems to work. Does anyone know what could be the problem? My carrier is AT&T. Do I need to reach out to them?

Thank you!