Why did a conversation close?
For everyone
A thread marked Closed in your Messages list was ended by one side, through the conversation's ⋮ menu.
The two ways it happens
- Close — either side ended it. The thread reads: "This conversation is closed. No new messages can be sent."
- Block — the stronger door. The thread reads: "This conversation is closed because one side blocked the other. No new messages can be sent."
What stays and what stops
The history stays readable on both sides — closing removes the future, not the past. No new messages can be sent in a closed thread, ever; even lifting a block does not reopen the conversation it closed.
The way back
A fresh introduction, accepted by both sides, opens a fresh conversation — the same way the first one started.