App Host version is unknown

On the Apps tab, the App Host version appears as Unknown.

When this problem occurs, you might not be able to select the App Host when you install an app.

To resolve this issue, follow these steps:
  1. On the App Host, type this command to restart it. 
    sudo restartAppHost

    When multiple App Hosts are detected, the system prompts you to select which one you want to restart.

  2. Wait for the App Host container to restart.

    To verify that the App Host containers are running correctly, see Checking the App Host and containers.