How To Fix XMS_ADM645 - RFC connection via destination '&1' was rejected by the server: "&2&3&4".

SAP Error Message - Details

• Message type: E = Error

• Message class: XMS_ADM - XMS - Administration

• Message number: 645

• Message text: RFC connection via destination '&1' was rejected by the server: "&2&3&4".

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 XMS_ADM645 - RFC connection via destination '&1' was rejected by the server: "&2&3&4". ?

  The SAP error message XMS_ADM645 indicates that an RFC (Remote Function Call) connection attempt via a specified destination was rejected by the server. The message typically includes details about the destination and the reason for the rejection.
  Causes:
  
  Network Issues: There may be network connectivity problems between the SAP system and the target server.
  Authorization Issues: The user credentials used for the RFC connection may not have the necessary authorizations to access the target system.
  Configuration Errors: The RFC destination may be incorrectly configured in the SAP system (e.g., incorrect hostname, port, or parameters).
  Server Availability: The target server may be down or not reachable due to maintenance or other issues.
  Firewall Restrictions: Firewalls or security settings may be blocking the connection attempt.
  SAP Gateway Issues: The SAP Gateway on the target system may not be running or may be misconfigured.
  
  Solutions:
  
  
  Check Network Connectivity:
  
  Use tools like ping or telnet to verify that the target server is reachable from the SAP system.
  Ensure that there are no network outages or issues.
  
  
  
  Verify RFC Destination Configuration:
  
  Go to transaction SM59 in the SAP GUI and check the configuration of the RFC destination.
  Ensure that the hostname, service (port), and other parameters are correct.
  
  
  
  Check User Authorizations:
  
  Ensure that the user credentials used for the RFC connection have the necessary authorizations in the target system.
  You can check user roles and authorizations in transaction SU01.
  
  
  
  Check Server Status:
  
  Verify that the target server is up and running.
  Check for any maintenance activities or downtime that might affect connectivity.
  
  
  
  Review Firewall Settings:
  
  Ensure that firewalls are configured to allow traffic on the required ports for RFC communication.
  Consult with your network/security team if necessary.
  
  
  
  Check SAP Gateway:
  
  Ensure that the SAP Gateway service is running on the target system.
  You can check the status of the gateway using transaction SMGW.
  
  
  
  Review Logs:
  
  Check the system logs (transaction SM21) and the developer trace files (transaction ST22) for any additional error messages that might provide more context.
  
  
  
  Related Information:
  
  
  Transaction Codes:
  
  SM59: RFC Destinations
  SM21: System Log
  ST22: Dump Analysis
  SMGW: Gateway Monitor
  SU01: User Maintenance
  
  
  
  Documentation: Refer to SAP Help Portal or SAP Notes for specific guidance related to RFC connections and troubleshooting.
  
  
  If the issue persists after checking the above points, consider reaching out to your SAP Basis team or SAP support for further assistance.