Unable to update or create reports in D365

Hi,

I face a weird issue while uploading reports in CRM.

1. Developed reports using VS2012 and uploaded in CRM - worked fine.

2. For some reason, VS2012 kept throwing me connectivity error in the data source using MS CRM Fetch Xml and as an alternative i had VS2015 with BIDS and Report Extension installed. I continued to develop the reports on VS2015.

3. When i try to upload the reports in CRM, got a generic error saying 

 <Message>An error occurred while trying to add the report to Microsoft Dynamics 365. Try adding the report again. If this problem persists, contact your system administrator.</Message>

Let me know the fix please.

Thanks

Bhuvi