Issue

During the execution of the application, the Mendix server generates the HTTP error code 499. The logs reflect the following messages:

"POST /xas/ HTTP/1.1" 499 227 22

and

x_cf_routererror:"endpoint_failure (context canceled)"

Environment

Studio Pro (all versions)

Cause

The HTTP status code 499 generally indicates that the client has closed the connection or has timed out before receiving a response from the server. Additionally, the logs may contain the header response_time. This log entry reflects the total duration required to process the request.

Solution/Workaround

The issue may arise from long-running queries or requests that require an extended duration to complete. It is advisable to investigate whether any long-running queries occurred during this timeframe.

If such queries are identified, it is recommended to explore optimization strategies for these long-running database queries within the application to reduce the duration for which connections remain open.

Furthermore, please be advised that if the microflow execution exceeds 3 seconds (response_time), it is advisable to implement an asynchronous call for the microflow.

Additional information 

• Running Operations Asynchronously | Mendix Documentation
• Asynchronous operations - Azure Architecture Center | Microsoft Learn
• Possible reason for NGINX 499 error codes | Stack Overflow
• On Click Event and Events Section | Mendix Documentation