Export Portal Report to Excel- Not able to pass report context

 Use Case:- Provide user an option to download assigned tasks detail.

I am using 'Export Portal Report to Excel' plugin for this use case & plugin configuration details are below.

Include_ Header_ Row: true
New_ Document_ Folder:"My Report"
New_ Document_ Name:"tasks details"
Report: "Task for Users"
Report_ Context:"my_user_id"
Sheet Number:0

Error:- There is a problem with task “Export Portal Report to Excel” in the process “export report”. The following error was raised by the Export to Excel function: For input string: "[Ljava.lang.String;@2ef1438a"

I can generate excel for those reports where report context not required but getting an error where the context requires.