CAML Query Builder for app web (add-in web)

Question

I am trying to generate a query using U2U CAML Query Builder for a list on an app web (add-in web). When I try to connect using credentials of the current user, which can connect to app web in the UI, I get the following error message:

System.Net.WebException: The remote server returned an error: (403) Forbidden.
at System.Net.HttpWebRequest.GetResponse()
at Microsoft.SharePoint.Client.SPWebRequestExecutor.Execute()
at Microsoft.SharePoint.Client.ClientContext.GetFormDigestInfoPrivate()
at Microsoft.SharePoint.Client.ClientContext.EnsureFormDigest()
at Microsoft.SharePoint.Client.ClientContext.ExecuteQuery()
at U2U.SharePoint.CAML.CSOM.CSOMSite.get_Title()
at U2U.CamlControlLibrary.SharePointHierarchyUserControl.AddWebHierarchy(QueryInfo queryInfo)
at U2U.CamlControlLibrary.SharePointHierarchyUserControl.Connect(QueryInfo queryInfo)
at U2U.CamlBuilder.MainForm.OpenSite()

Can someone recommend any other tool or tehnique to generate CAML queries for app web?

Answer 1

In the end, this error message was caused by SharePoint web application being configured to enable Windows authentication as well as one trusted Identity provider. So I guess CAML Query Builder got confused (or SharePoint maybe?).

Workaround for my problem was to copy folder containing the list to a new empty SharePoint farm solution, deploy the solution to host web (on a web application configured to use Windows authentication only), and then use CAML Query Builder to generate my query.

It is only a workaround so if anyone has a better answer I'll mark it as answer.