Data Source on uploaded report greyed out and not working - Oracle

Hi,

I am wondering if somebody can give me some advice....

I have created a simple test report on the desktop version of Power BI which hits my Oracle database fine.  Saving the same report on a Power BI Report Server and running it does not work even though the tnsnames information is correct.  

I have also noticed that the data source settings with in the report are greyed out:

However, I can create a data source on the Power BI Reporting server and test it fine:

I am fairly confident therefore the Oracle client info and tnsnames.ora server side are OK.  How do I go about playing with the data source on the uploaded report if it is greyed out?

Any help would be greatly appreciated.

Cheers