Value cannot be null. Parameter name: path1

Qt VS Tools is installed for VS2019.

1) Unable to launch Designer and Linguist, I get error:

Value cannot be null.
Parameter name: path1

Stacktrace:
at System.IO.Path.Combine(String path1, String path2)
at QtVsTools.Editors.Editor.GetStartInfo(String filePath, String qtToolsPath, Boolean hideWindow)
at QtVsTools.Editors.Editor.Start(String filePath, String qtToolsPath, Boolean hideWindow)

2) Unable to add a version, I get an error:

Value cannot be null.
Parameter name: path1

Stacktrace:
at System.IO.Path.Combine(String path1, String path2, String path3)