TR1907 Transformer cannot gain access to database

When a cube is automated to rebuild on a regular basis, transformer fails to create the cube due to the failed authentication. Transformer prompts for user password even if the prompt for password box is unchecked in the Signon Property Sheet and Include Access Manager auto-access in the model is checked in the authentication tab of Model Property Sheet.
Error Details:
(TR1907) Transformer can't gain access to database 'Database Name' with signon information 'username'. [->Cancel] PowerPlay Transformer
Reason:
The Database signon is not recognized by Transformer via Access Manager due to an incorrect database name. Database name specified within transformer needs to be exactly the same as the one set up within Access Manager. This is also case sensitive.

Use Access Manager to record the database authentication and set the auto-access to access manager's signon. Cognos common signons are set to flown from Access Manager user class as well as the database signon

Steps:

1. Create the data source in Access Manager Admin Console
2. Add user signos into the user class Administrator
3. Uncheck the box against Prompt for Password in the user signon property sheet
4. Within datasource property sheet, specify the datasource name, which should be exactly the same as the one in Access Manager. The datasource name is case sensitive.
5. Activate "Include Access Manager auto-access in the model" from Authentication tab of the Model Property Sheet