Skip to content
  • Solutions
    By Role
    • For Developers
    • For Content Managers
    • For Agencies
    • For IT Admins
    • For Web Hosters
    • For Developers
    • For Content Managers
    • For Agencies
    • For IT Admins
    • For Web Hosters
    By Infrastructure
    • Overview
    • AWS
    • Microsoft Azure
    • Alibaba Cloud
    • Google Cloud Platform
    • Vultr
    • Overview
    • AWS
    • Microsoft Azure
    • Alibaba Cloud
    • Google Cloud Platform
    • Vultr
    • Digital Ocean
    • Linode
    • Upcloud
    • Oracle
    • OVH
    • Digital Ocean
    • Linode
    • Upcloud
    • Oracle
    • OVH
  • Product
    • Plesk Features
    • Plesk Editions
    • What’s new
    • Pricing
    • Roadmap
    • Lifecycle Policy
    • Extensions Catalogue
  • Pricing
  • Extensions
    Featured Extensions
    • SocialBee
    • WP Toolkit
    • Sitejet Builder for Plesk
    • SEO Toolkit
    • Joomla! Toolkit
    • Premium Email
    • Email Security
    • SocialBee
    • WP Toolkit
    • Sitejet Builder for Plesk
    • SEO Toolkit
    • Joomla! Toolkit
    • Premium Email
    • Email Security
    Bundles and packs:
    • Business and Collaboration Edition
    • WP pack
    • Hosting pack
    • Power pack
    • Language pack
    • Business and Collaboration Edition
    • WP pack
    • Hosting pack
    • Power pack
    • Language pack

    See all Extensions

  • For Partners
    • Plesk Contributor Program
    • Plesk Partner Program
    • Affiliate program
    • Plesk University
  • Help Center
    • Documentation
    • Professional Services
    • Support
    • Contact Us
    • Wiki
    • Forum
  • Plesk 360 login
  • Free Trial
  • Pricing
  • Solutions
    • By Role
      • For Developers
      • For Content Managers
      • For Agencies
      • For IT Admins
      • For Web Hosters
    • By Infrastructure
      • Overview
      • Plesk on Amazon Web Services (AWS & Lightsail)
      • Microsoft Azure
      • Alibaba Cloud
      • Google Cloud Platform
      • Vultr
      • DigitalOcean
      • Linode
      • UpCloud
      • Oracle
      • OVH
  • Products
  • Pricing
  • Extensions
    • Featured Extensions
      • SocialBee
      • WP Toolkit
      • Sitejet Builder for Plesk
      • SEO Toolkit
      • Joomla! Toolkit
      • Premium Email
      • Email Security
    • Bundles and packs:
      • Business and Collaboration Edition
      • WP pack
      • Hosting pack
      • Power pack
      • Language pack
      • See all Extensions
  • For Partners
    • Plesk Contributor Program
    • Plesk Partner Program
    • Affiliate Program
    • Plesk University
  • Help Center
    • Documentation
    • Professional Services
    • Support
    • Contact Us
    • Wiki
    • Forum
  • Plesk 360 login
  • Free Trial
  • Pricing
  • Solutions
    • By Role
      • For Developers
      • For Content Managers
      • For Agencies
      • For IT Admins
      • For Web Hosters
    • By Infrastructure
      • Overview
      • Plesk on Amazon Web Services (AWS & Lightsail)
      • Microsoft Azure
      • Alibaba Cloud
      • Google Cloud Platform
      • Vultr
      • DigitalOcean
      • Linode
      • UpCloud
      • Oracle
      • OVH
  • Products
  • Pricing
  • Extensions
    • Featured Extensions
      • SocialBee
      • WP Toolkit
      • Sitejet Builder for Plesk
      • SEO Toolkit
      • Joomla! Toolkit
      • Premium Email
      • Email Security
    • Bundles and packs:
      • Business and Collaboration Edition
      • WP pack
      • Hosting pack
      • Power pack
      • Language pack
      • See all Extensions
  • For Partners
    • Plesk Contributor Program
    • Plesk Partner Program
    • Affiliate Program
    • Plesk University
  • Help Center
    • Documentation
    • Professional Services
    • Support
    • Contact Us
    • Wiki
    • Forum
  • Plesk 360 login
  • Free Trial
Plesk 360 login
Free Trial

Knowledge Base

Unable to access website: [pool example.com] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 1 idle, and 49 total children

 
apachechildrendomainsfastcgigo

Symptoms

  • Plesk Obsidian running on a Linux-based operating system
  • Unable to access website the website example.com with 502 Bad Gateway or 503 Service Temporarily Unavailable errors showing in a browser
  • The following error can be found in the log file for the PHP version that this website is configured to use (for example /var/log/plesk-php74-fpm/error.log):

    WARNING: [pool example.com] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 0 idle, and 129 total children

  • The Apache error log for the website /var/www/vhosts/example.com/logs/example.com/error_log contains an error that is similar to the following:

    AH01067: Failed to read FastCGI header, referer: https://example.com/testpage.php

Cause

Some or all values for the PHP FastCGI Process Manager (PHP-FPM) directives below were exceeded by the related website:

  • pm.start_servers
  • pm.min_spare_servers
  • pm.max_spare_servers

Resolution

Apply one of the solutions below:

Solution I

  1. Log into Plesk.
  2. Go to Domains > example.com > PHP Settings > PHP-FPM settings section.
  3. Change pm from dynamic to ondemand:
  4. Press the OK button to apply the hcnage

    Note: after applying the steps above, the RAM consumption and load on the server can be increased

Solution II

  1. Log into Plesk.
  2. Go to Domains > example.com > PHP Settings > PHP-FPM settings section.
  3. Increase values for the directives pm.start_servers, pm.min_spare_servers, pm.max_spare_servers and press the OK button to apply the changes:

Additional information

Plesk for Linux services logs and configuration files

PHP: Configuration - Manual

Tweet
Share
Share
Email
0 Shares
Read the full article
Related Posts

How to Host a Go App on Plesk

Read More »

Your Complete .htaccess Guide: Including .htaccess Basics and More

Read More »

NGINX vs Apache – Which Is the Best Web Server in 2024?

Read More »
Knowledge Base

How to configure Apache to process PHP code inside an .html file on a Plesk server

Read More »

[BUG] nginx shows configuration error in Plesk: “proxy_read_timeout” directive is duplicate

Read More »

Website on Plesk server is not accessible: 504 Gateway Time-out: The timeout specified has expired: [client 203.0.113.2:54693] AH01075: Error dispatching request to

Read More »

Websites hosted on Plesk server are unavailable with 502 Bad Gateway: upstream sent too big header while reading response header

Read More »

Hosting Wiki

  • Django
  • Server Redundancy
  • Linux Containers
  • Google Cloud CDN
  • CGI
  • Bare Metal Server
  • PhpMyAdmin
  • phpPgAdmin
  • Oracle VM Server
  • Server Virtualization Software
  • Windows Server
  • Linux
  • PHP
  • MongoDB
  • Domain
  • Plesk
  • Apache Tomcat
  • Apache
  • Web Server
  • DNS Server
  • HTTP
X-twitter Linkedin Youtube Reddit Github
  • Product
  • Login
  • Pricing
  • Editions
  • For Partners
  • Partner Program
  • Contributor Program
  • Affiliate Program
  • Plesk University
  • Company
  • Blog
  • Careers
  • Events
  • About Plesk
  • Our Brand
  • Resources
  • User and Admin guides
  • Help Center
  • Migrate to Plesk
  • Contact Us
  • Hosting Wiki
  • Forum
  • Legal
  • Legal
  • Privacy Policy
  • Imprint

© 2025 WebPros International GmbH

Part of the WebPros®  Family