My customers can still chat with us after all agents have gone offline. Why is this happening?
In Zendesk Chat, once a chat has begun, an agent does not have the ability to end the chat on behalf of the customer. The connection is still open until the customer ends the chat. For other reasons that a chat session could end, see the article: When do chats time out?
If a customer starts a chat, and then the conversation completes, and the agent ends the chat in the user interface, the customer could still have the chat dialogue open and begin a chat conversation that will not be answered. This can cause confusion because there are no agents to take the chat.
It is possible to write a custom script that ends a chat as soon as an account goes offline.
<!--Callback to end chat when account goes offline -->
For more information, consult the Chat API documentation.