Trouble updating JSON source in service

Hi,

My report is based on a live api based on JSON. Updating the source in the desktop report is no problem. However, when published to the service and trying to update the report then gives the following error:

"error":{"code":"DM_GWPipeline_Gateway_MashupDataAccessError","pbi.error":{"code":"DM_GWPipeline_Gateway_MashupDataAccessError","parameters":{},"details":[{"code":"DM_ErrorDetailNameCode_UnderlyingErrorCode","detail":{"type":1,"value":"-2147467259"}},{"code":"DM_ErrorDetailNameCode_UnderlyingErrorMessage","detail":{"type":1,"value":"We found extra characters at the end of JSON input."}},{"code":"DM_ErrorDetailNameCode_UnderlyingHResult","detail":{"type":1,"value":"-2147467259"}},{"code":"Microsoft.Data.Mashup.ValueError.Reason","detail":{"type":1,"value":"DataFormat.Error"}}],"exceptionCulprit":1}}} Table: Deltakerinfo.

Appreciate anye help!

Thanks