Website on Plesk is not accessible: 500.19 - Internal Server Error

Symptoms

• Unable to access the website the following error occurs:

  CONFIG_TEXT: The page can not be displayed because an internal server error.

• One of the following errors is shown when detailed errors option is set in IIS:

  CONFIG_TEXT: HTTP Error 500.19 - Internal Server Error.
  The requested page cannot be accessed because the related configuration data for the page is invalid.
  Detailed Error Information: Module CustomErrorModule
  Notification SendResponse
  Handler PHP-php
  Error Code 0x80070021
  Config Error Lock violation
  Config File \\\\?\\C:\\Inetpub\\vhosts\\example.com\\httpdocs\\web.config
  Requested URL http://www.example:80/index.php/
  Physical Path C:\\Inetpub\\vhosts\\example.com\\httpdocs\\index.php\\
  Logon Method Anonymous
  Logon User Anonymous
  Config Source:
  4: <httpErrors>
  5: <clear />
  6: <error statusCode="400" path="C:\\Inetpub\\vhosts\\example.com\\error_docs\\bad_request.html" />

  Or:

  CONFIG_TEXT: Warning
  -SET_RESPONSE_ERROR_DESCRIPTION
  ErrorDescription
  Absolute physical path "C:\inetpub\custerr\401.htm" is not allowed in system.webServer/httpErrors section in web.config file. Use relative path instead.

  Or:

  CONFIG_TEXT: Severity
  Event
  Module Name
  135. view trace Warning -SECURITY_DENIED_BY_MIMEMAP
  FileName C:\INETPUB\VHOSTS\EXAMPLE.COM\HTTPDOCS\JOB\INDEX.PHP
  CONFIG_TEXT: 136. view trace Warning -MODULE_SET_RESPONSE_ERROR_STATUS
  ModuleName StaticFileModule
  Notification EXECUTE_REQUEST_HANDLER
  HttpStatus 404
  HttpReason Not Found
  HttpSubStatus 3
  ErrorCode The request is not supported.
  (0x80070032)
  ConfigExceptionInfo StaticFileModule

Cause

%plesk_vhosts%/example.com/httpdocs/web.config file is either corrupted or points to non-existent or wrongly configured error pages.

Resolution

1. Connect to the server via RDP.

2. Move the web.config file out of %plesk_vhosts%/example.com/httpdocs/ folder.

3. Recreate the web.config file with:

   C:\> plesk repair web example.com

4. Review the custom web.config file and set correct values for error pages under the <httpErrors> section.