How To Fix SNC021 - Logon with external ID only possible with SNC-secured connection

SAP Error Message - Details

• Message type: E = Error

• Message class: SNC - Secure Network Communication, SNC

• Message number: 021

• Message text: Logon with external ID only possible with SNC-secured connection

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message SNC021 - Logon with external ID only possible with SNC-secured connection ?

  The SAP error message SNC021 indicates that a logon attempt using an external ID (such as an SNC name) is only possible when the connection is secured with Secure Network Communications (SNC). This error typically arises in environments where SNC is configured for secure communication, but the connection being used is not secured.
  Cause:
  
  Insecure Connection: The connection to the SAP system is not using SNC, which is required for logon with an external ID.
  Configuration Issues: The SNC settings in the SAP system or the client may not be properly configured.
  Network Issues: There may be network issues preventing the establishment of an SNC-secured connection.
  
  Solution:
  To resolve the SNC021 error, you can take the following steps:
  
  
  Ensure SNC is Enabled:
  
  Verify that SNC is enabled on both the SAP server and the client. Check the SNC parameters in the SAP profile (e.g., snc/enable should be set to 1).
  
  
  
  Use an SNC-Secured Connection:
  
  Make sure that the connection string or parameters used to connect to the SAP system specify that an SNC-secured connection should be used. This typically involves using the appropriate SNC name in the connection string.
  
  
  
  Check SNC Configuration:
  
  Review the SNC configuration settings in the SAP system. Ensure that the SNC library is correctly installed and configured.
  Check the SNC_LIB parameter in the SAP profile to ensure it points to the correct SNC library.
  
  
  
  Client Configuration:
  
  If you are using a client (like SAP GUI), ensure that it is configured to use SNC. This can usually be done in the SAP GUI options under the "Logon" settings.
  
  
  
  Network Configuration:
  
  Ensure that there are no network issues preventing the establishment of an SNC-secured connection. This may involve checking firewalls, VPNs, or other network security settings.
  
  
  
  Consult Documentation:
  
  Refer to the SAP documentation for detailed instructions on configuring SNC and troubleshooting related issues.
  
  
  
  Related Information:
  
  SNC (Secure Network Communications): A security protocol that provides encryption and authentication for SAP communications.
  External ID: An identifier used in SNC logon that is typically associated with a user in an external security system.
  SAP Notes: Check for relevant SAP Notes that may provide additional guidance or updates related to SNC and this specific error message.
  
  If the issue persists after following these steps, consider reaching out to your SAP Basis team or SAP support for further assistance.