Columns has been created in the sharepoint list but not loading while we are giving the "Load from sharepoint list" option

Issue 1: We are trying to use the ‘Load from SharePoint List’ option to setup our data mappings for Notes to SharePoint, but we are getting a 403 forbidden error. 

The connection to the general SharePoint site is successful and we can browse all the lists. We just can’t load from a specific list. 

Error:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Net.WebException: The request failed with HTTP status 403: Forbidden.

Issue 2: Can't able to create the lookup column in the Quest tool, while provide the lookup target field option it throws the  " Unable to connect the (site url)" error. But the site has been connected in the intial connection