Site shows: 500.19 - Internal Server Error, Config Error - Lock violation

Symptoms

• Website is showing error:

  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 IIS Web Core
  Notification BeginRequest
  Handler Not yet determined
  Error Code 0x80070021
  Config Error Lock violation
  Config File \\?\C:\Inetpub\vhosts\example.com\web.config

• The following error can be found if Failed Request Tracing is enabled:

  CONFIG_TEXT: ModuleName
  IIS Web Core
  Notification 1
  HttpStatus 500
  HttpReason Internal Server Error
  HttpSubStatus 19
  ErrorCode 2147942433
  ConfigExceptionInfo \\?\C:\Inetpub\vhosts\example.com\httpdocs\web.config (80) :Lock violation
  Notification BEGIN_REQUEST
  ErrorCode The process cannot access the file because another process has locked a portion of the file.
  (0x80070021)

• Prohibit the ability to override handlers via web.config is enabled in Tools & Settings > Security Policy.

Cause

Prohibit the ability to override handlers via web.config blocks attempts to set custom handlers in web.config.

Resolution

Apply one of the following solutions:

• Change the default Security Policy on the server

  1. Log into Plesk

  2. Untick Prohibit the ability to override handlers via web.config in Plesk > Tools & Settings > Security

     In case the issue is still present, apply the following steps

     1. Connect to the server via RDP

     2. Repair the configuration:

        C:\> plesk repair web example.com

     3. Create backup of C:\windows\system32\inetsrv\config\applicationHost.config and open it with a text editor

     4. Remove lockElements="" from the <handlers> section of the affected website

• Modify the web.config of the affected server:

  1. Log into Plesk

  2. Navigate to Domains > example.com > File Manager and open the web.config file for editing

  3. Remove the <handlers> section from the file and save it

     Note: The section may differ. The initial error will point at the line that holds the offending configuration: \\?\C:\Inetpub\vhosts\example.com\httpdocs\web.config (80)