Hello, I'm testing the trial version of telerik report server. However, I have a problem ... after generating a report in telerik report design R2 2018, I can not see it in the report server. It always generates the following error:

"Unable to establish a connection to the database. Please verify that your connection string is valid. In case you use a named
connection string from the application configuration file, make sure the name is correct and the connection string settings are present
in the configuration file of your application.
------------- InnerException -------------
Format of the initialization string does not conform to specification starting at index 0."

I configured web.config to use my database connection (Oracle), and in my report (in the format ".trdp") I configured the same connection.
Within report design, my report is working but in report server does work.

Can you help me?

Hello Marcel,

When working with server reports, the connection string needs to be embedded in the report definition, or (recommended) used by a name registered in Report Server Data Connections. The Data Connections are managed through the DATA page in the Report Server Management Console. This page allows to register a new connection or edit/delete existing one. Once registered in Data Connections, the connection can be referred by name by all the reports stored in Report Server. The server data connections are available when designing a server reports - they will be listed in the Choose data connection page of the Configure SQL Data Source wizard.

I shot a small movie demonstrating how to create a data connection to Oracle database and then create a report that uses that connection. The report can be previewed in the Standalone Designer and in the Report Server Management Console. The video can be seen here: https://www.screencast.com/t/VKmJACId (please note that it has no sound and requires Adobe Flash to run). I hope you will find it useful, but if you have further questions, please do not hesitate to ask.

Regards,
Ivan Hristov
Progress Telerik

Thanks for your help. I understood where I was wrong. Their service was very good.