How To Fix TG891 - Exception & raised; no application servers found

SAP Error Message - Details

• Message type: E = Error

• Message class: TG - Messages for Upgrade Repository Switch

• Message number: 891

• Message text: Exception & raised; no application servers found

What causes this issue?

The message server cannot be reached or does not give a list of
application servers available. The most common reason for this exception
is the missing message server. In the working directory of the SAP
system, you can find the trace file "dev_ms".

System Response

The upgrade stops with an error message.

How to fix this error?

Start the message server again, by restarting the SAP system, for
example. Using the test environment of the function module
TH_SERVER_LIST, check that the message server is running correctly.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message TG891 - Exception & raised; no application servers found ?

  The SAP error message TG891 indicates that there is an exception raised due to the system not being able to find any application servers. This can occur in various scenarios, such as when trying to log into the SAP system or when executing a transaction that requires application server access.
  Causes:
  
  Network Issues: There may be network connectivity problems preventing the client from reaching the application servers.
  Application Server Down: The application servers may be down or not running.
  Configuration Issues: The SAP system configuration may be incorrect, leading to the inability to locate application servers.
  Load Balancer Issues: If a load balancer is used, it may not be routing requests correctly to the available application servers.
  SAP Instance Not Registered: The SAP instance may not be registered properly in the SAP message server.
  Firewall Restrictions: Firewalls may be blocking access to the application servers.
  
  Solutions:
  
  Check Network Connectivity: Ensure that the network connection between the client and the application servers is stable and functioning.
  Verify Application Server Status: Check if the application servers are up and running. You can do this by using transaction code SM51 to view the list of active application servers.
  Review SAP Configuration: Check the SAP profile parameters and ensure that the configuration for the message server and application servers is correct.
  Check Load Balancer Settings: If a load balancer is in use, verify that it is configured correctly and that it can reach the application servers.
  Restart SAP Services: If the application servers are down, try restarting the SAP services on those servers.
  Check SAP Router Configuration: If you are using an SAP router, ensure that it is configured correctly to allow traffic to the application servers.
  Firewall Settings: Review firewall settings to ensure that they are not blocking access to the application servers.
  
  Related Information:
  
  Transaction Codes: Use transaction codes like SM51 (to check active servers), SM04 (to see user sessions), and SM12 (to check for locks) for troubleshooting.
  SAP Notes: Check SAP Notes related to the TG891 error for any specific patches or updates that may address the issue.
  System Logs: Review system logs (transaction SM21) for any additional error messages or warnings that could provide more context about the issue.
  SAP Support: If the issue persists, consider reaching out to SAP support for further assistance, providing them with detailed logs and error messages.
  
  By following these steps, you should be able to diagnose and resolve the TG891 error in your SAP environment.