PBIRS 404 Bad Request when trying to change Connection String from PowerBIReports(id)/DataSources ap

[bspiteri001]

Hi we recently started a server changeover for an SQL which was hosting the PowerBI Report Server. We have migrated the database and the encryption key and everything was a success. However now we wanted to change the connection string to point to the new server. 

The reports are connected using the SQL Server connection and they are all in import mode. 

Due to the fact that we had lots of reports we thought of automating this process through the use of the API. So what we did is we used the API endpoint identified in the subject and get the result, then we used the result in the value key and pasted it in the body and used the patch. 

However we are getting an HTTP 400 Bad Request message. Can you please advise the reason for this? 

Thanks

[bspiteri001]

All the reports do not use parameter connections and therefore for us, we cannot update through parameter