IE SSO Error - Apache log found "http 401" error code and using SSO "SPNEGO" with IE and solution

The error on the client side:

Event 3, Security-Kerberos

There are Error Code: 0x7 KDC_ER_S_PINCIPAL_UNKNOWN

 

Solution:

Remove the duplicated SPN

Example: setspn -d http/daserver1.reskit.contoso.com daserver1

 

Reference:
https://technet.microsoft.com/en-us/library/cc731241(v=ws.11).aspx#BKMK_examples

IE SSO Error - Apache log found "http 401" error code and using SSO "SPNEGO" with IE and solution