How To Fix TB404 - No connection to remote system or error in communications

SAP Error Message - Details

• Message type: E = Error

• Message class: TB - SM31 table maintenance messages

• Message number: 404

• Message text: No connection to remote system or error in communications

What causes this issue?

No link to remote system &v1& or incorrect communications

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?

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message TB404 - No connection to remote system or error in communications ?

  The SAP error message TB404, which indicates "No connection to remote system or error in communications," typically arises when there is a failure in the communication between SAP systems or between an SAP system and an external system. This can occur in various scenarios, such as during remote function calls (RFC), IDoc processing, or when using other communication protocols.
  Causes of TB404 Error
  
  
  Network Issues: Problems with the network connection, such as firewalls blocking traffic, network outages, or incorrect routing.
  
  
  Configuration Errors: Incorrect settings in the RFC destination or the logical system configuration in SAP.
  
  
  System Availability: The remote system may be down or not reachable due to maintenance or other issues.
  
  
  Authorization Issues: The user or service account may not have the necessary permissions to access the remote system.
  
  
  Protocol Mismatch: Incompatibility between the communication protocols used by the systems.
  
  
  SAP Gateway Issues: Problems with the SAP Gateway service, which is responsible for handling communication requests.
  
  
  Solutions to TB404 Error
  
  
  Check Network Connectivity:
  
  Verify that the network connection between the systems is active.
  Use tools like ping or traceroute to check connectivity.
  
  
  
  Review RFC Destination:
  
  Go to transaction SM59 and check the configuration of the RFC destination.
  Ensure that the connection type, target host, and service are correctly configured.
  
  
  
  Check System Status:
  
  Ensure that the remote system is up and running.
  Check for any scheduled maintenance or downtime.
  
  
  
  Review Authorizations:
  
  Ensure that the user or service account has the necessary authorizations to perform the required actions on the remote system.
  
  
  
  Check SAP Gateway:
  
  Ensure that the SAP Gateway is running properly. You can check the status using transaction SMGW.
  Restart the gateway if necessary.
  
  
  
  Review Logs:
  
  Check the system logs (transaction SM21) and the developer traces (transaction ST22) for any additional error messages that might provide more context.
  
  
  
  Test Connection:
  
  Use the "Test Connection" feature in transaction SM59 to verify that the RFC destination can connect to the remote system.
  
  
  
  Consult Documentation:
  
  Review SAP Notes and documentation related to the specific error message for any additional troubleshooting steps or patches.
  
  
  
  Related Information
  
  SAP Notes: Search for relevant SAP Notes in the SAP Support Portal that may address specific issues related to TB404.
  Transaction Codes:
  
  SM59: RFC Destinations
  SMGW: SAP Gateway Monitor
  SM21: System Log
  ST22: Dump Analysis
  
  
  Network Tools: Familiarize yourself with network diagnostic tools that can help identify connectivity issues.
  
  If the issue persists after following these steps, it may be necessary to involve your network or SAP Basis team for further investigation.