MIAW Chat Session Not Ending Automatically After Agent Lefts Chat (Customer Can Still Respond After 24 Hours) 

Workaround : 

Due to a limitation in Messaging for In-App and Web (MIAW), customer sessions can remain active for up to 48 hours. Additionally, agents are unable to end the chat directly because the "End Chat" button is not available once they claim the conversation and click on "Customer Inactivity." 

Salesforce has recommended a workaround to allow agents to manually close the session. After clicking "Customer Inactive" and leaving the conversation, the agent can:

1. Navigate to the Messaging Session User details (which will be listed as a Guest) for that Messeging Session Record ,Details.
2. Click on the Guest user, which will redirect to the conversation window.
3. From the messaging session record's dropdown menu, the agent will now see the "Close Customer Session" option.

Selecting this option will close the session on the agent’s side. As a result, if the customer returns after a long period of inactivity, they will start a new session and be required to fill out the pre-chat form again.

To enable this functionality, we edited the "Messaging for In-App and Web Agent" permission set by adding the "End Messaging Session" permission. This allows agents to see and use the "Close Conversation" button.