Configuring Kerberos Authentication for certsrv web application

I'm trying to configure Kerberos authentication for use with the certsrv web application on Windows Server 2012R2. I've set the providers to be Negotiate:Kerberos in the Authentication settings in IIS for certsrv yet every time I try to login using Kerberos I get an Invalid Username/Password error. This does not happen when I login using NTLM. 

Any guidance?