Once You get error: The permissions granted to user ‘Domain\User’ are insufficient for performing this operation. (rsAccessDenied)
Go to > Start Menu > start Internet Explorer as “Run as Administrator”
Open Your Report Server URL
Go to Site Settings
Security->New Role Assignment
In the Report Manager website, click Folder Settings.
Click New Role Assignment.
Enter the domain’s Domain Users group, and tick the Browser role. This will mean that any user can view all reports by default. Click OK to create the role.
Also add your user name as content manager
The new Role Assignment will now be showing.
Add username to the Site Setting so that we can launch report sever website without administrative privilege
Go to Site Setting
Click New Role Assignment
Add user as system administrator