How To Fix PU751 - Communication error: System &1 (see below for details)

SAP Error Message - Details

• Message type: E = Error

• Message class: PU - Upgrade and Transport Log Messages

• Message number: 751

• Message text: Communication error: System &1 (see below for details)

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.

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Smart SAP Assistant

• What is the cause and solution for SAP error message PU751 - Communication error: System &1 (see below for details) ?

  The SAP error message PU751, which indicates a "Communication error: System &1," typically arises during communication between different SAP systems or between an SAP system and an external system. This error can occur in various contexts, such as during data transfer, remote function calls (RFC), or when using SAP Business Connector.
  Causes:
  
  Network Issues: Problems with the network connection between the systems can lead to communication errors. This could be due to firewalls, routing issues, or network outages.
  Configuration Errors: Incorrect configuration settings in the RFC destination or in the SAP system can cause communication failures.
  System Availability: The target system may be down or not reachable due to maintenance or other issues.
  Authorization Issues: The user or service account used for the communication may not have the necessary authorizations to access the target system.
  Protocol Mismatch: If there is a mismatch in the communication protocols or versions between the systems, it can lead to errors.
  Timeouts: Long-running processes may exceed the timeout settings, leading to communication errors.
  
  Solutions:
  
  Check Network Connectivity: Ensure that the network connection between the systems is stable and that there are no firewalls or network policies blocking the communication.
  Verify RFC Destination: Go to transaction SM59 in the SAP GUI and check the configuration of the RFC destination. Ensure that the connection parameters are correct and that the connection test is successful.
  System Status: Check if the target system is up and running. You can do this by trying to log in to the target system or checking its status in the SAP system monitoring tools.
  Review Authorizations: Ensure that the user or service account has the necessary authorizations to perform the required actions in the target system.
  Check Logs: Review the system logs (transaction SM21) and the application logs (transaction SLG1) for any additional error messages or details that can provide more context about the issue.
  Adjust Timeout Settings: If timeouts are an issue, consider adjusting the timeout settings in the RFC destination configuration.
  Consult SAP Notes: Check the SAP Support Portal for any relevant SAP Notes that may address this specific error or provide additional troubleshooting steps.
  
  Related Information:
  
  Transaction Codes: 
  
  SM59: RFC Destinations
  SM21: System Log
  SLG1: Application Log
  
  
  SAP Support: If the issue persists after trying the above solutions, consider reaching out to SAP Support for further assistance. Provide them with detailed information about the error, including any logs or screenshots that can help diagnose the problem.
  
  By following these steps, you should be able to identify and resolve the communication error associated with the PU751 message.