1) Click on MIME Types :-
Action Pen :- Add
FileName Extension :- .axd
MIME Type :- application/octet-stream
2) Click on Handler Mapping :-
Action pan Click Add Manage Handler
Then Enter
Request path :- Reserved.ReportViewerWebControl.axd
Type :- Microsoft.Reporting.WebForms.HttpHandler
Name :- Reserved-ReportViewerWebControl-axd
Action Pen :- Add
FileName Extension :- .axd
MIME Type :- application/octet-stream
2) Click on Handler Mapping :-
Action pan Click Add Manage Handler
Then Enter
Request path :- Reserved.ReportViewerWebControl.axd
Type :- Microsoft.Reporting.WebForms.HttpHandler
Name :- Reserved-ReportViewerWebControl-axd
Now Restart The IIS MUST