I am developing an SSRS report for a Dynamics 365 client. I have developed reports for other clients without any issues, but for some reason I am unable to add any custom attributes to the FetchXML without getting the error mentioned above. I have set up the Data Source connection string as follows:
https://[MyClientInstance].crm.dynamics.com;[UniqueNameFromDeveloperResources]
I used Advanced Find to develop the initial query and then copied the FetchXML in the Query window of the Data Source in SSRS. I am able to refresh the fields. I am also able to run the FetchXML in the Query Designer window. It returns records, including all custom fields, without a problem.
The only time I am having an issue with the query is when I attempt to preview the report.
I am using Visual Studio 2015.