Remove Google Hangouts conversations from Messages?

I used to use Messages to talk to people on Google Hangouts, but recently whenever I try to respond it says, "Support for the targeted service Google Talk has been discontinued."

The weird thing is, I still receive messages from Google Hangouts conversations. I just can't respond. I've tried deleting this conversation too, but it just keeps popping back up whenever the person responds to me.

I don't want to block this person from messaging me. I just want this specific conversation to stop showing up.

I've tried changing my messages preferences to only be reachable at my phone number instead of through email too, but that didn't change anything.