Open channels and group channels can be freezed and unfreezed. When a channel is freezed, only the operators can send messages to the channel and users aren't allowed to chat.
Open channels can be freezed only by using Chat API or on Sendbird Dashboard. To freeze an open channel, go to Chat > Open channels on the dashboard, select an open channel, and click the Freeze icon at the upper right corner. To unfreeze, select the frozen channel and click the Freeze icon again.
Group channels can be freezed by operators using the Chat SDK as shown below.