Close window with index is failing in Firefox

@Amit.Lacher The ‘Close window with index’ addon is failing in Firefox. It is working in all other browsers.

Error message:

ConnectionFailedException: Unable to establish websocket connection to http://localhost:61292/devtools/browser/d9705e71-0026-4b51-baf6-afdd60c95df3
Build info: version: '4.1.1', revision: 'e8fcc2cecf'
System info: host: 'E580-PMEERA', ip: '', 'Windows 10', os.arch: 'amd64', os.version: '10.0', java.version: '13.0.1'
Driver info: driver.version: RemoteWebDriver

What would be the reason?