How To Fix /SAPAPO/ND421 - Logon to SAP system failed

SAP Error Message - Details

• Message type: E = Error

• Message class: /SAPAPO/ND -

• Message number: 421

• Message text: Logon to SAP system failed

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

Unfortunately, there isn't any extra information in this error notice.

What else can you do?

First, use our AnswerBot below to get a possible cause and solution (requires a premium subscription).

Also, review the in-depth Common Questions & Answers listed below; you could discover a solution there or be able to connect with others who have faced similar challenges.

You can also try searching the SAP support portal (support.sap.com) but you need a special user ID to access it. It is possible that an SAP support note exists that provides additional details about the mistake or even steps for fixing it.

Smart SAP Assistant

• What is the cause and solution for SAP error message /SAPAPO/ND421 - Logon to SAP system failed ?

  The SAP error message /SAPAPO/ND421 Logon to SAP system failed typically indicates that there is an issue with the connection to the SAP system, particularly in the context of SAP Advanced Planning and Optimization (APO). This error can arise due to various reasons, and here are some common causes, potential solutions, and related information:
  Causes:
  
  Incorrect Credentials: The username or password used to log in may be incorrect.
  User Lockout: The user account may be locked due to multiple failed login attempts.
  Network Issues: There may be network connectivity problems between the client and the SAP server.
  SAP System Down: The SAP system may be down for maintenance or due to an unexpected outage.
  Authorization Issues: The user may not have the necessary authorizations to access the SAP system.
  Configuration Issues: There may be configuration issues in the SAP system or in the connection settings.
  
  Solutions:
  
  Check Credentials: Verify that the username and password are correct. If necessary, reset the password.
  Unlock User Account: If the account is locked, contact your SAP administrator to unlock it.
  Network Troubleshooting: Check the network connection to ensure that the client can reach the SAP server. This may involve checking firewalls, VPNs, or other network configurations.
  System Status: Confirm that the SAP system is up and running. You can check with your system administrator or use monitoring tools.
  Authorization Check: Ensure that the user has the necessary authorizations to access the SAP system. This may require checking roles and profiles assigned to the user.
  Review Configuration: Check the connection settings in the SAP GUI or any middleware being used to connect to the SAP system. Ensure that the system ID, instance number, and other parameters are correctly configured.
  
  Related Information:
  
  SAP Notes: Check SAP Notes for any known issues or patches related to this error. You can search the SAP Support Portal for relevant notes.
  Logs: Review the SAP system logs (transaction SM21) for any additional error messages or information that may provide more context about the failure.
  SAP Community: Engage with the SAP Community forums to see if other users have encountered similar issues and what solutions they found effective.
  Documentation: Refer to the official SAP documentation for troubleshooting connection issues and understanding the configuration settings.
  
  If the issue persists after trying the above solutions, it may be necessary to involve your SAP Basis team or technical support for further investigation.