The HTTP request is unauthorized with client authentication scheme 'Ntlm' The authentication header received from the server was 'NTLM'

Question

I know there\'s a lot of questions on SO similar to this, but I couldn\'t find one for this particular issue.

A couple of points, first:

• I have n

Answer 1

This issue was even more strange for us. Everything worked if you had previously visited the sharepoint site from the browser, before you made the SOAP call. However, if you did the SOAP call first we'd throw the above error.

We were able to resolve this issue by installing the sharepoint certificate on the client and adding the domain to the local intranet sites.