Problems with group messages

Hey all,

I'm having some issues with group messaging on my S20. I've never had an issue with sending things in group chats before, so this is quite frustrating. My settings haven't changed at all, but for some reason, I can't send messages in a couple of group chats.

I thought maybe someone in the chat blocked me, but I'm still able to post things in other chats with the same members. I tried restarting my phone, but same issue. What do you guys think might be causing this problem?