Why does my xMatters web server display a blank page when I attempt to access the web user interface?

I am attempting to access xMatters via the web user interface, but the web server displays only a blank page. When I attempt to access the web UI via a fronting server, I get a 502 Proxy Error. How do I access xMatters?


This issue can be identified by one of the following symptoms:

  • When attempting to access xMatters web user interface directly, the browser displays only a blank page.
  • When attempting to access xMatters web user interface via a fronting server (such as Apache HTTP server), the browser displays an error message similar to the following:
502 Proxy Error  
Proxy Error  
The proxy server received an invalid response from an upstream server.  
The proxy server could not handle the request GET  
Reason: Error reading from remote server

The <xMHOME>\webserver\logs\main.log file should also record an error similar to the following:

2010-03-17 17:41:58,303 [pool-1-thread-8] WARN - handle failed  
java.io.IOException: FULL  
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:266)  
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)  
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)  
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:396)  
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)  
at java.lang.Thread.run(Thread.java:595)


This issue is caused by the setting for the headerBufferSize in the Jetty configuration being too small compared to the HTTP headers contained in your request. The default value, 3072 bytes, is sufficient for most cases, but if you are using a proxy server, load balancer, SiteMinder for SSO (or any combination), a number of HTTP headers can be added to each request.

You can address the issue by increasing the buffer size for HTTP headers in Jetty.


To increase the Jetty buffer size:

  1. Open the <xMHOME>\webserver\etc\jetty.xml file.
  2. Locate the "headerBufferSize" parameter.
  3. Increase the value to the number of bytes you want to allocate for headers.
  4. Save and close the jetty.xml file.
  5. Restart the xMatters web server.

xMatters Reference

DTN-2253, SUP-3874, JDN-1177

Originally created by Don Clark

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