How To Fix SNC020 - Unexpected error (RC=&1) at logon with external ID

SAP Error Message - Details

• Message type: E = Error

• Message class: SNC - Secure Network Communication, SNC

• Message number: 020

• Message text: Unexpected error (RC=&1) at logon with external ID

What causes this issue?

Unknown return code &V1& during logon with external identification.

System Response

The logon was refused.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message SNC020 - Unexpected error (RC=&1) at logon with external ID ?

  The SAP error message SNC020, which indicates an "Unexpected error (RC=&1) at logon with external ID," typically relates to issues with Secure Network Communications (SNC) during the logon process. This error can arise from various underlying causes, and here are some common causes, potential solutions, and related information:
  Causes:
  
  SNC Configuration Issues: Incorrect or incomplete configuration of SNC parameters in the SAP system or the client.
  SNC Library Problems: The SNC library (e.g., SAP Cryptographic Library) may not be installed correctly or may be incompatible with the current SAP version.
  Network Issues: Problems with the network connection that prevent proper communication between the client and the SAP server.
  User Credentials: Issues with the user credentials being used for the logon, such as expired passwords or incorrect external IDs.
  Certificate Issues: Problems with the digital certificates used for SNC, such as expired or untrusted certificates.
  Authorization Issues: The user may not have the necessary authorizations to log in using SNC.
  
  Solutions:
  
  
  Check SNC Configuration:
  
  Verify the SNC parameters in the SAP system (e.g., snc/enable, snc/gssapi_lib, snc/identity/as).
  Ensure that the SNC settings in the SAP GUI or other clients are correctly configured.
  
  
  
  Update or Reinstall SNC Library:
  
  Ensure that the latest version of the SAP Cryptographic Library is installed and properly configured.
  Check for compatibility with the SAP system version.
  
  
  
  Network Troubleshooting:
  
  Test the network connection between the client and the SAP server.
  Check for any firewall or proxy settings that may be blocking the connection.
  
  
  
  Verify User Credentials:
  
  Ensure that the user ID and password are correct and that the account is not locked or expired.
  If using an external ID, verify that it is correctly configured in the SAP system.
  
  
  
  Check Certificates:
  
  Verify that the digital certificates used for SNC are valid and trusted.
  If necessary, renew or replace expired certificates.
  
  
  
  Review Authorizations:
  
  Check the user's authorizations to ensure they have the necessary permissions to log in using SNC.
  
  
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to SNC errors for specific guidance and troubleshooting steps. Some relevant notes may include:
  
  Note 123456 (example, replace with actual note numbers relevant to your issue).
  
  
  SNC Documentation: Review the official SAP documentation on SNC configuration and troubleshooting.
  Logs and Traces: Analyze the SAP system logs (SM21) and traces (ST01, ST05) for more detailed error messages that can provide additional context for the issue.
  
  If the problem persists after trying the above solutions, consider reaching out to SAP support for further assistance, providing them with detailed information about the error and the steps you have already taken.