Crystal Reports: Database Logon Failed

Question

I have application in ASP.NET (C#) in which I use Sap Crystal Reports for Visual Studio. In VS everything works perfect. But when I deploy it to IIS \"Database Logon Failed\" er

Answer 1

I had an awful time with this Crystal issue, the report worked locally and on another server, but would not work on our production environment.

The issue was SQL Native client not being installed on the Prod server. We modified the reports to use OLEDB.

Report Designer -> 
Right Click on Background -> 
Database -> 
Set Datasource location -> 
In the 'Replace With:' section, Create a New Connection using OLE DB (ADO) -> 
Microsoft OLE DB Provider for SQL Server

We had been selecting SQL Server Native Client 11.0, and this was causing the error on deployment.

Prior to this, I had tried everything, x86/x64, app pool changes, installing crazy versions of Crystal 13, this was it.