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

SNC020 - Overview

• 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.

SNC020 - Details

• 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