McAfee Anti-virus software appears to block ProSelect from communicating with Adobe Lightroom Classic. 

To determine if McAfee is blocking this communication, turn off the Mcafee Firewall and try to export.  If it works with the Firewall off, follow the steps below to resolve the issue and create an ongoing solution.

1) Open the Total Protect Console.

2) Click the Settings (gear icon) on the top right.

3) Click Firewall.

4) Click the Manage Rules button for Network Connections.

5) Click the Lock icon to make changes. Enter your system password for your computer.

6) Click the + Button just above to add a new custom rule.

7) Enter a rule name of Allow Lightroom - ProSelect, or similar.

8) Under Transport Protocol, ensure it has TCP - Local Ports selected and enter 9191 in the number file.

9) Click Save.

Once this has been completed, communication should be allowed between PS and Lightroom.