Connecting into Microsoft Lists/ Sharepoint via API - Error 409

Hello all, good afternoon.

I am facing an issue whenever connecting into the sharepoint folder / list using the api version 14.

"DataSource.Error: SharePoint: Request failed: The remote server returned an error: (409) Conflict. (Conflict)"

Interestingly whenever I change to the apiversion 15, it retrieves the data accordingly. 

Unfortunately I have a lot of columns that have different names when using the api 15 , for some reason some column names have less characters, no spaces, etc, so I would need to remap everything once again and was trying to find another solution.

Thanks in advance!