There are several causes for this error. Ultimately, they are all because crystal reports cannot log on to the tables in the database, so it must be determined what is causing the connection to fail.
Codeless Platforms have advised that Crystal Reports should be using an OLEDB connection within the report as this is more stable and reliable.
To check the connection type and/or update the connection type, follow these steps:
Open the report in crystal designer.
In the menu bar, click Database and select Set Datasource Location.
On the Current Data Source, expand the properties node. The details of the connection saved in the report are now displayed.
To change the connection type, follow these steps:
In the Replace With pane, expand OLE DB.
Double-click Make New Connection.
Enter the Server details, user credentials of an account to log into the SQL server and select the database to connect to.
Click Next
Click Finish.
Expand your new connection, dbo, tables.
Update each table by selecting it in the Current Data Source pane.
Select the relevant table under the Replace With pane and click Update.
When all tables have been updated, click Close.
Save the report template.
Open the failing task in TaskCentre.
Open the crystal report step.
Import the update report template into the task.
Apply the credentials in the Database Tables Logon Information.
Apply any Mapped Report Parameters.
Click OK to save the step.
Click OK to save the Task.
Queue the task.