Logon Failure

I have W2003 server with Sql running. User is trying to open a report from the database. It was working fine.
Message pops up stating:
The report server cannot open a connection to the report server database. The logon failed. (rsReportServerDatabaseLogonFailed) Get Online Help Logon failure: unknown user name or bad password. Any help would be appreciated.
i am also getting the same issue, if you got any solution please let me know|||I'm also getting the logon failed error when using a data driven subscription to the report and the query validation is succesful, anyone knows how to fix that?
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Cehck your data source connection. Make sure the account has enought permissions to access the database.

|||Tried it with sa account, the same error...