No, a 1-to-1 channel is not terminated if one user leaves the channel. The channel will still exist and the remaining user can continue to send messages to the channel.
For example, let’s say User A and User B are having a private 1-to-1 conversation in a group channel. If User B decides to leave the channel, the channel will still exist and User A can continue to send messages. However, User B will no longer receive any messages from User A since they have left the channel.
Please note that if both the users leave the channels then Sendbird removes the empty channel by default.
