Did you read all these notes? It's important for SPNEGO.
1832706 - SPNego ABAP: Fixes for Algorithms AES128, AES256, DES
1819808 - SPNego ABAP: Collective Corrections
1798979 - SPNego ABAP: Downport
--> the note gives you all the minimum levels of the kernel and SP versions you need to do SPnego ABAP
--> also lists a ton of notes to review at the very bottom.
1732610 - SPNego ABAP: Troubleshooting Note
--> good note to review if you are having problems with SPnego.
And you put in all the correct profile params? Could you show us?
Also, what's in your SPNEGO (tcode)?
how about DOS command "klist", what does it say?
and did you install secure login client on your PC? does the name in that match the SNC tab for your ID in SU01?
what kernel version are you at?