My sharepoint web services fail when i add forms based authentication to my web application. Currently I work on a desktop application that migrates data to Sharepoint. We employ webservices to perform most tasks. If i create or change a web application in SharePoint 2013 to use mixed mode authentication both windows NTLM and Forms based authentication, all my web services fail with the following error
Error: Could not locate or create SharePoint Document Library Documents. URL: http://sharepoint.local The HTTP request was forbidden with client authentication scheme 'Ntlm'.
I have tried to implement this fix but it didn't resolve my issue. If i turn off forms based authentication it works again. Also, another weird result of turning on Forms based auth is that my lists that include any External Content types fail to render. These are all implemented using Secure store ids.
Lastly, I can use the client context to login with a forms based user and access the list but all legacy web service calls fail.