Logon failed when attempting to run report

When attempting to run a report, the following error appeared.
What does the following error message mean?
Logon failed.
Logon failure: unknown user name or bad password. (Exception from HRESULT:
0x8007052E)Looks like your report credentials are not set.
Go to Report Manager, navigate to the report, go to properties and make
sure your data sources are all correctly set up