Power BI SSRS 2016 server not enter into SSRS URL

Hi,

In my customize c# code i am sending SSRS subscription to users mail directly through SSIS.

I am getting the error when code reaching to one of the ReportingService2010 webservice method.

Subscritpions[] sub = rs.ListSubscriptions("ReportPath")

ReportPath = https://<server>/ReportServer/Pages/ReportViewer.aspx?%2fxxx%2fyyy%2fzzz+bbb+ccc%2faaa&rs:Command=Render

Note: xxx, yyy,(zzz+bbb+ccc)are folder name into my report structure.

I am getting this below error when breakpoint hits to rs.ListSubscriptions method.

The path of the item 'https://<server>/ReportServer/Pages/ReportViewer.aspx?%2fxxx%2fyyy%2fzzz+bbb+ccc%2faaa&rs:Command=Render' is not valid.
The full path must be less than 260 characters long; other restrictions apply.
If the report server is in native mode, the path must start with slash. ---> Microsoft.ReportingServices.Diagnostics.Utilities.InvalidItemPathException: \
The path of the item 'https://<server>/ReportServer/Pages/ReportViewer.aspx?%2fxxx%2fyyy%2fzzz+bbb+ccc%2faaa&rs:Command=Render' is not valid. The full path must be less than 260 characters long; other restrictions apply.
If the report server is in native mode, the path must start with slash.

Please help with your suggestions what is the wrong i am doing in this.