Since release 1.8.14 the Kerberos authentication via mod_auth_kerb is not working any more. The NTLM authentication is also effected. The problem is related to the server side with Apache.
The topic is discussed in the following 2 links:
A possible solution is described here: http://svn.haxx.se/dev/archive-2015-10/0058.shtml
I applied the patch to release 1.8.14 and build it on Linux.