IIS and PHP error 500, "The parameter is incorrect. (0x80070057)" in FastCgiModule

Question

I have PHP 8.0.28 in IIS 10.0 (Windows Server 2022), the fastcgi module is configured correctly and working as it should in most cases, but sometimes I get 500 error when I make a request, even for the same url requested in the most of the time it responds with a 200 status, but sometimes it responds with a 500 error. This instability makes me think of a bug either in PHP or in IIS or in the way they communicate.

Unfortunately no errors appear in the OS events, nor does PHP catch any errors, I was able to get information about the error using IIS tracing.

Answer 1

Hi @Max Mayer,

Please check the IIS logs for any information about the 500 error. The logs can be found in the default location: %SystemDrive%\inetpub\logs\LogFiles.

If you have enabled Failed Request Tracing (FRT), FRT will provide detailed information about request processing, including any errors or warnings encountered. The failed request log files can be found in the default location: %systemdrive%\inetpub\logs\FailedReqLogFiles\W3SVC.

Also, intermittent 500 errors may be caused by resource exhaustion. You can try monitoring server resources such as CPU, memory, and disk usage with tools like Performance Monitor (perfmon) or Resource Monitor to analyze resource usage at the time the error occurred.

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Best regards,

Yurong Dai

Answer 2

I don't see anything useful in the XML data. You can also check in the HTTP error logs.

C:\Windows\system32\LogFiles\HTTPERR

If this is an intermittent error, then to me that would indicate that it is data or activity related.

Check the request monitor and look to see if you have a large number of requests that are executing. You might also have a request running that is locking some backend database table which impacts the site. Have your database team check the activity in the DB instance.

https://inthetechpit.com/2019/11/10/check-incoming-requests-iis-with-request-monitor/

You can also check that from a "run as admin" powershell prompt.

Get-Website | Get-WebRequest | format-table -property Hostname, timeElapsed, clientIpAddress, Url

Have your web site developer check the PHP code for the page that crashes the most, and make sure that there is a try/catch code block that will capture any error. Write any error back to the client and also to a log file. See if you can pinpoint the call/statement that crashes.

You can also open the XML file with Edge and then reload the page in IE mode from the menu to look at it formatted. You might see something there.

Answer 3

Finally I managed to figure out what the problem is, the PHP opcache module evidently has a problem with shared memory and when the number of visits increases, the server crashes

Faulting application name: php-cgi.exe, version: 8.0.28.0, time stamp: 0x63eb7b04
Faulting module name: php_opcache.dll, version: 8.0.28.0, time stamp: 0x63eb7e4f
Exception code: 0xc0000005
Fault offset: 0x0000000000168011
Faulting process id: 0x1f2c
Faulting application start time: 0x01d9d3b2249e086e
Faulting application path: /path/to/php-cgi.exe 
Faulting module path: /path/to/php_opcache.dll

Thanks for your help