3778002 - Could not validate SPNEGO token. Reason: No user with user attributes

SPNEGO authentication is failing in a JAVA Portal scenario

The following error is seen in the Troubleshooting Wizard logs:

com.sap.security.core.server.jaas.SPNegoLoginModule                     OPTIONAL    ok          exception             true       Could not validate SPNEGO token. Reason: No user with user attributes [[namespace=com.sap.security.core.usermanagement, name=uniquename, value= user ID, isCaseSensitive=false]] found
        #1 com.sap.security.spnego.legacy = false
        #2 com.sap.spnego.jgss.name = HTTP/*
        #3 com.sap.spnego.uid.resolution.attr = uniquename
        #4 com.sap.spnego.uid.resolution.mode = simple

SAP NetWeaver Application Server Java

SPNego, token, AS JAVA, Realm, Principal, Kerberos, Logon ID, KPN, UME, uniquename,  No user with user attributes, user, SPN, service principal name , KBA , BC-JAS-SEC-LGN , Logon, SSO , Problem