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Help needed with 502.6 error [Answered]RSS

3 replies

Last post Jul 27, 2020 08:59 AM by Jon_Boy

  • Help needed with 502.6 error

    Jul 16, 2020 03:19 PM|Jon_Boy|LINK


    I am seeing intermittent 502.6 errors and need some help to troubeshoot further, please.

    I have found documentation that explains that the error is "502.6 Forwarded request failure (ARR)" however I have not found anything which explains more about what this means. I am seeing the error on a Windows Server 2016 system with ARR 3.0. The farm being routed to is just a local Wildfly instance at There are planty of calls routed without issue and just a very few that generate the 502.6 error.

    The log also records (for sc-win32-status) 12152 which I believe means "The server response cannot be parsed." However I am unclear on what this actually means. The errorr seem to happen three times in a row and are associated with a call to a web service which transfers a file.

    Any pointers gratefully received as my searches have failed to yield any leads so far.

    Thanks in advance.

  • Re: Help needed with 502.6 error

    Jul 16, 2020 06:12 PM|lextm|LINK


    Unless you go deeper to the packets, it won't be possible to know why.

    Lex Li
    Want to have a chat on the issues you meet? Find me at https://booktime.xyz/p/lextm
    This posting is provided "AS IS" with no warranties, and confers no rights.
  • Re: Help needed with 502.6 error

    Jul 17, 2020 03:41 AM|Yuk Ding|LINK

    Hi Jon_Boy,

    We can't find much document about how to fix 502.6. So we need to enable both failed request tracing and etl log to trace winhttp and winet.

    The way to capture etl would looks like this

    logman create trace "winhttp" -ow -o winhttp.etl -p "Microsoft-Windows-WinHttp" 0xffffffffffffffff 0xff -nb 16 16 -bs 1024 -mode Circular -f bincirc -max 4096 -ets
    @echo off
    ECHO Reproduce your issue and enter any key to stop tracing
    @echo on
    logman stop "wininet" -ets

    However, it require network monitor or dedicated software to review these logs. So if this issue is making business impact, you can open a support ticket to involve professional support engineer.


    Best Regards,

    Jokies Ding

    Yuk Ding

    MSDN Community Support
    Please remember to "Mark as Answer" the responses that resolved your issue.
  • Re: Help needed with 502.6 error

    Jul 27, 2020 08:59 AM|Jon_Boy|LINK

    The issue was being caused by the size of the POST exceeding the limit set in WildFly for POST requests. This resulted in WildFly terminating the connection.

    Thanks for suggestions. I'm posting the answer in case it helps anyone in the future.