Root cause: 

SNC configured at SAP GUI but not at the SAP.

Solution:

either disable SNC at the SAP GUI (“Network” tab of the SAP Logon entry) or configure / enable SNC at the SAP server.

SAP Support component:

• BC-FES-GUI if this is just a configuration issue with regards to SAPUILandscape.xml or the installation of SNC.
• For the SNC configuration itself, including at the SAP server, the correct component is BC-SEC-SNC.

Additional test that can be performed:

• Logon to the SAP system (e.g., without SNC), access the transaction RZ11 and display the value of the parameter “snc/enable”. It will be zero.
• At SAP GUI end, executing the NwCheckWorkstation as per SAP Note 1099439 Installation check for SAP GUI -to check the installation of GUI and SNC.