smbspool_krb5_wrapper does not tell CUPS that it requires negotiate for authentication. Patch will follow.
Created attachment 13392 [details] patch for 4.6
Created attachment 13393 [details] patch for 4.7
Reassigning to Karolin for inclusion in 4.7.0, 4.6.next.
(In reply to Jeremy Allison from comment #3) Pushed to autobuild-v4-{6,7}-test.
(In reply to Karolin Seeger from comment #4) Pushed to both branches. Closing out bug report. Thanks!