Publishing paginated report error

I created a paginated report that pulls data from 2 different datasets that are on different workspaces. 

I would now like to publish the report to one of those workspaces so that I can put it inside one of my pbi reports.

However, I'm getting the following error:

Operation returned an invalid status code 'BadRequest'
DMTS_CreateMonikerDatasourceErrorCode:

ErrorCode: PaginatedReportConnectionStringIsInvalid
Details: The connection string of some datasources are invalid. Please check the connection string.