Custom Activity Error : Cannot create unknown type


I have created a custom activity and added in UiPath Studio without any issues but now when I used this activity and run it gives me following error:

Cannot create unknown type
Source: System.Xaml
Exception Type: XamlObjectWriterException

Please help to resolve this issue.

@dear.saxena Did you find a resolution to this problem? I am experiencing the same error but with ReadCsvFile.