Impossible to establish video session with the server error - Security Center 5.9 - 5.13

If you receive an Error: Impossible to establish video session with the server message, there might be a problem with the server, the Media Router role, the Federation™ role, the Archiver role, or the video unit. To troubleshoot the issue, learn about the possible causes and their respective solutions.

1. Make sure that your server is running.
2. Make sure that the Archiver role is online:
   1. In the Config Tool Video task, select the Archiver role.
   2. At the bottom of the Video task, click Maintenance > Diagnose ().
   3. Fix any issues that are found.
3. If you are trying to view a federated camera, confirm that the Security Center Federation™ role is online:
   1. In the Config Tool System task, click the roles view.
   2. Select the Federation role and click Maintenance > Diagnose ().
   3. Fix any issues that are found.
4. If you are trying to view a federated camera, confirm that the server for the federated Security Center system is online.
5. It might be a Media Router connection problem. Make sure that the Media Router role is online:
   1. In the Config Tool System task, click the Roles view.
   2. Select the Media Router role and click Maintenance > Diagnose ().
   3. Fix any issues that are found.
6. Restart the Media Router role:
   1. In the Config Tool System task, click the Roles view.
   2. Select the Media Router role and click Maintenance > Deactivate role ().
   3. In the confirmation dialog box that opens, click Continue.
      The Media Router turns red.
   4. At the bottom of the System task, click Maintenance > Activate role ().
7. Make sure that the unit is online.
   If the unit is red in the Roles and units view, then troubleshoot why the video unit is offline.