How To Fix FRE644 - RFC undefined Error

SAP Error Message - Details

• Message type: E = Error

• Message class: FRE - F&R CON R/3 - Messages

• Message number: 644

• Message text: RFC undefined Error

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 FRE644 - RFC undefined Error ?

  The SAP error message FRE644, which indicates "RFC undefined error," typically arises in the context of Remote Function Call (RFC) communications between SAP systems or between an SAP system and an external system. This error can occur due to various reasons, and understanding the cause is essential for troubleshooting and resolving the issue.
  Causes of FRE644 RFC Undefined Error
  
  
  Network Issues: Problems with the network connection between the SAP systems can lead to RFC errors. This includes issues like firewalls blocking the connection, network outages, or misconfigured network settings.
  
  
  RFC Destination Configuration: The RFC destination may not be correctly configured in the SAP system. This includes incorrect parameters such as the target system's IP address, system number, or client.
  
  
  Authorization Issues: The user credentials used for the RFC call may not have the necessary authorizations to execute the requested function module.
  
  
  Function Module Not Found: The function module being called may not exist in the target system, or it may be incorrectly named.
  
  
  Version Mismatch: There may be a version mismatch between the calling and target systems, especially if they are running different versions of SAP.
  
  
  System Load or Performance Issues: High load on the target system can lead to timeouts or failures in processing RFC calls.
  
  
  Solutions to FRE644 RFC Undefined Error
  
  
  Check Network Connectivity: Ensure that there is proper network connectivity between the systems. You can use tools like ping or traceroute to diagnose network issues.
  
  
  Verify RFC Destination: Go to transaction SM59 in the SAP GUI and check the configuration of the RFC destination. Ensure that all parameters are correct, including the target system's details.
  
  
  Check Authorizations: Verify that the user credentials used for the RFC call have the necessary authorizations to execute the function module. You can check this in transaction SU01.
  
  
  Validate Function Module: Ensure that the function module being called exists in the target system and is correctly named. You can check this in transaction SE37.
  
  
  Check System Versions: Ensure that both systems are compatible and running supported versions of SAP. If there are significant differences, consider upgrading or patching the systems.
  
  
  Monitor System Performance: Use transaction SM50 or SM66 to monitor the performance of the target system. If the system is under heavy load, consider optimizing performance or scheduling the RFC calls during off-peak hours.
  
  
  Review Logs: Check the system logs for any additional error messages or warnings that may provide more context about the issue. You can use transaction SM21 to view the system log.
  
  
  Test RFC Connection: Use the "Test Connection" feature in transaction SM59 to verify that the RFC destination is working correctly.
  
  
  Related Information
  
  SAP Notes: Check SAP Notes for any known issues or patches related to the FRE644 error. You can search for relevant notes in the SAP Support Portal.
  Documentation: Review the SAP documentation for RFC and related components to understand the configuration and troubleshooting steps better.
  Community Forums: Engage with the SAP Community or forums for additional insights and solutions from other users who may have encountered similar issues.
  
  By systematically checking these areas, you should be able to identify and resolve the FRE644 RFC undefined error in your SAP environment.