How To Fix 55403 - Internal error: message classification &1, message type

SAP Error Message - Details

• Message type: E = Error

• Message class: 55 - Messages for development class EENO

• Message number: 403

• Message text: Internal error: message classification &1, message type

What causes this issue?

The message classification for the IS-U message object contains an
invalid <DS:DE.EMSG_TYP>message typing.</> This is a program error that
can only be rectified by SAP.

System Response

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

How to fix this error?

Note the following:
transaction
entries leading to the error
message text
and send a problem message to SAP.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message 55403 - Internal error: message classification &1, message type ?

  The SAP error message 55403, which states "Internal error: message classification &1, message type," typically indicates an issue related to the message processing system within SAP. This error can arise in various contexts, such as during the processing of messages in the SAP system, particularly in modules like SAP PI/PO (Process Integration/Process Orchestration) or when dealing with IDocs (Intermediate Documents).
  Possible Causes:
  
  Configuration Issues: Incorrect configuration of message types or classifications in the system.
  Data Issues: Invalid or unexpected data being processed, which does not conform to the expected format or structure.
  System Bugs: Internal bugs or inconsistencies in the SAP system that may lead to unexpected behavior.
  Transport Issues: Problems with the transport of messages between different systems or environments.
  Authorization Issues: Lack of necessary authorizations for the user or process trying to send or receive the message.
  
  Solutions:
  
  Check Configuration: Review the configuration settings for the message types and classifications in the relevant transaction codes (e.g., WE20 for IDocs, SPRO for general configuration).
  Validate Data: Ensure that the data being processed is valid and conforms to the expected structure. This may involve checking the source data or the mapping logic if using PI/PO.
  Review Logs: Check the application logs (transaction SLG1) or system logs (transaction SM21) for more detailed error messages that can provide additional context.
  Update SAP: If the error is due to a known bug, check for SAP Notes or patches that address the issue. You can search the SAP Support Portal for relevant notes.
  Test in a Development Environment: If possible, replicate the issue in a development or test environment to isolate the cause without affecting production.
  Contact SAP Support: If the issue persists and cannot be resolved through the above steps, consider reaching out to SAP Support for assistance.
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as WE02 (for monitoring IDocs), SLG1 (for application logs), and SM37 (for job monitoring).
  SAP Notes: Regularly check SAP Notes for updates or known issues related to your specific version of SAP.
  Documentation: Review SAP documentation for the specific module you are working with, as it may provide insights into common issues and their resolutions.
  
  By following these steps, you should be able to diagnose and potentially resolve the error message 55403 in your SAP system.