Cannot connect to the License Manager
On the end-user machine, the following message might appear if the ArcGIS software cannot connect to the license manager:
The server (lmgrd) has not been started yet, or the wrong port@host or license file is being used, or the port or hostname in the license file has been changed. Feature: ARC/INFO Server Name: server1 License Path @server1 FLEXlm Error: -15, 10. System Error: 10061"WinSock: Connection refused."
There are two variations of this error.
Error 1
FLEXlm Error: -15, 10. System Error: 10061"WinSock: Connection refused."
Error 2
FLEXlm Error: -15, 29. System Error: 10061"Winsock: Connection refused."
Causes
The ArcGIS license manager is not running. This could be due to a number of reasons. Check the status of the license manager and restart the license service if required. View the debug log file for more information on errors.
Solutions

Starting with ArcGIS License Manager 2019.0 (Linux platforms only), the FlexNet licensing service must be installed as a separate step following install of the setup. If the FlexNet licensing service is not installed, this will result in issues where clients cannot connect to the ArcGIS License Manager. Please see the topic License Manager installation and startup for more information.