Error when releasing report and it is asking for username and password but it should

[Varun]

while releasing this SSRS(Sql server report service) it should not ask for password
and after clicking on view-report it gives following error

An error occurred during client rendering.
An error has occurred during report processing. (rsProcessingAborted)
Cannot create a connection to data source 'test31'. (rsErrorOpeningConnection)
ORA-12154: TNS:could not resolve the connect identifier specified