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ARM Agent Log Shows "Close Code: 1001 - Connection Reset, Reconnect Expected" After ARM Platform Maintenance

Publish Date: Jun 28, 2026
Description

This article applies to On-Premises and Hybrid deployments only.
CloudHub 1.0, CloudHub 2.0, and Runtime Fabric (RTF) are not affected.

Background

After Anypoint Runtime Manager (ARM) platform maintenance, a small number of On-Premises or Hybrid Mule Runtimes may incorrectly display "Connected" status (expected status is "Running") for a short period of time, within approximately 10 minutes (though recovery is often faster), even though they are locally running normally.

This can be caused by a race condition during ARM platform restarts, where a stale status update overwrites the correct "Running" status. The Runtime itself is healthy — only the reported status is incorrect.

Resolution

To address this, MuleSoft has implemented the self healing process — an automated mechanism that safely resets the small subset of Runtimes that are incorrectly stuck in "Connected" status.

When this happens, customers may observe the following log in ARM Agent log (mule-agent.log)

Example:

ERROR 2026-06-23 10:54:40,086 [WebSocketInboundExecutor] [processor: ; event: ]
com.mulesoft.agent.transport.handlers.GenericWebSocketHandler: 
Closing Mule Agent WebSocket – Close Code: 1001 – Close Reason: MuleId 115916 connection reset, reconnect expected
INFO  2026-06-23 10:54:40,086 [WebSocketInboundExecutor] [processor: ; event: ]
com.mulesoft.agent.transport.handlers.GenericWebSocketHandler: Mule Agent WebSocket closed
INFO  2026-06-23 10:54:40,201 [pool-14-thread-1] [processor: ; event: ]
com.mulesoft.agent.transport.connections.AsynchHttpWSConnectionThread: Initializing Mule Agent WebSocket connection
INFO  2026-06-23 10:54:40,201 [pool-14-thread-1] [processor: ; event: ]
com.mulesoft.agent.transport.connections.AsynchHttpWSConnectionThread: 
Mule Agent WebSocket connecting to host: runtime-manager.anypoint.mulesoft.com
INFO  2026-06-23 10:54:40,993 [WebSocketInboundExecutor] [processor: ; event: ]
com.mulesoft.agent.transport.handlers.GenericWebSocketHandler: Opening Mule Agent WebSocket
INFO  2026-06-23 10:54:41,013 [WebSocketInboundExecutor] [processor: ; event: ]
com.mulesoft.agent.transport.handlers.GenericWebSocketHandler: Mule Agent WebSocket opened
INFO  2026-06-23 10:54:41,013 [pool-14-thread-1] [processor: ; event: ]
com.mulesoft.agent.transport.connections.AsynchHttpWSConnectionThread: 
Mule Agent WebSocket connection was initialized after: 1 attempts
INFO  2026-06-23 10:54:41,672 [WebSocketInboundExecutor] [processor: ; event: ]
com.mulesoft.agent.services.security.HandshakeAuthorizationService: 
WebSocket Client connection authorized

 

What we are seeing:

  • "Closing Mule Agent WebSocket – Close Code: 1001 – Close Reason: MuleId 115916 connection reset, reconnect expected" This explicitly indicates a safe, intentional reconnection triggered from server (ARM Platform) by the Self-Healing process, not a network failure. (Note, the "115916" in this example is the server/runtime Id. You will see different Ids for your servers)
  • "Mule Agent WebSocket connecting to host: runtime-manager.anypoint.mulesoft.com" This indicates the ARM Agent triggered the reconnection to ARM Platform
  • "WebSocket Client connection authorized" This indicates the connection was successful

 

Additional Resources

Note:

If your mule-ageng.log is seeing "Close Code: 1006 - Close Reason: Connection was closed abnormally" (instead of "WebSocket - Close Code: 1001"), the code 1006 is not related to the self-healing process.  Close Code 1006 indicates an unexpected connection loss caused by a network-layer issue. 

Reference: WebSocket Close Codes: 1000, 1001, 1006 & All Others

Knowledge Article Number

005387931

 
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