Answer

When upgrading to 19.3 or later from a version earlier than 19.3.0.20190603, users must follow the steps below. If users do not follow these instructions, they may experience "Unable to connect to server" or "An unexpected error occurred" errors that prevent pages from loading, or be unable to log out of Hub.   

These errors are caused by a large load on Keycloak (User Management). They are especially prevalent in the Chrome browser. If you are installing a new Hub instance on 19.3 or higher (rather than upgrading an existing instance), you will not need to follow the instructions below.

1. Open the User Administration Console in Hub. 
   • You can access this by clicking the User Administration Console link at the bottom of the Hub login screen, or by going to https://{host}/auth/admin/master/console.
2. Navigate to Clients in the left menu.
3. Click tasktop.
4. Fill in Base URL and Admin URL both with https://localhost:8443.
   • If you have configured Hub to run HTTPS on a port other than 8443, change the URL above to use that port.
   • Note: Using localhost may not work for certain server configurations. If you are unable to logout after completing this step, you will need to update the Base URL and Admin URL to the fully qualified domain name of your Hub server (e.g., https://my.server.name.com:8443).
5. Click Save.
6. Restart the Hub service.

If you have altered Hub to use a keystore other than the default insecure keystore, you must also update Keycloak's standalone.xml file to reference that secure keystore.

Note: If you are upgrading from a version that is also earlier than 19.2.1, please additionally follow instructions here.