"<...>" does not have a valid License Manager. Please enter a valid License Manager Server

Error Message

When connecting to ArcGIS License Manager through ArcGIS Administrator, the following error is returned:

Error:   
"<…>" does not have a valid License Manager. Please enter a valid License Manager Server.

Cause

This error is returned because the firewall is not configured to allow connections to ArcGIS License Manager.

Solution or Workaround

Create new inbound and outbound rules to allow connections to ArcGIS License Manager. Refer to the 'Configure the firewall' solution section in Problem: Unable to connect to License Manager for more information.