ArcGIS Pro cannot obtain a license from the License Manager in a secured environment

Description

This issue has been encountered in ArcGIS Pro 2.7.3 using License Manager 2020.

When authorizing ArcGIS Pro Concurrent Use in a secured environment, a system message is returned:

An ArcGIS Pro Standard concurrent use license is not authorized.

 

Troubleshooting steps described in the article Problem: Unable to connect to ArcGIS License Manager have already been explored:

• License Manager is up and running
• Licenses are available
• TCP ports from 27000 to 27009 are open
• DNS from the ArcGIS Pro machine and License Manager machine are well recognized
• Both machines can communicate together (ping)

Cause

In addition to communicating in TCP with the License Manager on ports 27000-27009, ArcGIS Pro also communicates via another protocol that is normally blocked, FTP_DATA_ActiveMode.

FTP_DATA_ActiveMode : In the active mode, the client starts listening on a random port for incoming data connections from the server (the client sends the FTP command PORT to inform the server on which port it is listening).

Solution or Workaround

Enable FTP DATA Active Mode protocol in the firewall.