403 forbidden error when trying to 'Load from SharePoint List'

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.

I also have the full error log if needed.