Step-by-step help for your hosting

• How to fix Cloudflare Error 520: Web server is returning an unknown error

  Cloudflare Error 520 means your origin server sent an empty, invalid or unexpected response. Learn the usual causes on hosting and how to fix error 520 step by step.

  IntermediatecPanel hosting2 min read

• How to fix a 429 Too Many Requests error

  A 429 Too Many Requests error means a rate limit was hit. Learn who applies it (server, firewall, Cloudflare or an API), and how to fix 429 errors as a visitor and as a site owner.

  BeginnercPanel hosting3 min read

• How to fix a 414 Request-URI Too Long error

  A 414 Request-URI Too Long error means the URL is longer than the server accepts. Find out what creates huge URLs, such as redirect loops and long query strings, and how to fix them.

  IntermediatecPanel hosting2 min read

• How to fix a 408 Request Timeout error

  A 408 Request Timeout means the server gave up waiting for your browser to finish sending the request. Learn the causes, from slow connections to large uploads, and the fixes.

  BeginnercPanel hosting2 min read

• How to fix a 405 Method Not Allowed error

  A 405 Method Not Allowed error means the server rejects the HTTP method used, such as POST or PUT. Learn the causes on hosting and how to fix forms, APIs and rewrites.

  IntermediatecPanel hosting2 min read

• How to fix a 401 Unauthorized error

  A 401 Unauthorized error means the page needs valid login details. Find out why it appears, how password-protected directories cause it, and how to fix it.

  BeginnercPanel hosting2 min read

• How to fix a 400 Bad Request error

  A 400 Bad Request error means the server could not understand the request. Learn the common causes, from bad URLs to oversized cookies, and how to fix each one.

  BeginnercPanel hosting3 min read

• Fix CORS errors: "No 'Access-Control-Allow-Origin' header"

  Understand browser CORS errors when a frontend calls an API on another domain, and fix them correctly in the app, Nginx or Apache, including preflight requests and credentials.

  IntermediateLinux VPS · cPanel hosting3 min read

• Fix PHP session errors: save path, permissions and lost logins

  Fix session_start() errors and users being logged out: session.save_path permissions, full disks, garbage collection, cookie settings, multiple servers and Redis sessions.

  IntermediatecPanel hosting · Linux VPS3 min read

• Fix PHP cURL error 28 and other outgoing request errors

  Fix cURL error 28 (operation timed out), error 6 (could not resolve host) and error 7 (failed to connect) when PHP, WordPress or Laravel call external APIs.

  IntermediatecPanel hosting · Linux VPS3 min read

• Fix common Laravel errors after deployment

  Fix the Laravel errors that appear most after deploying: 500 with no message, 419 Page Expired, No application encryption key, storage permissions, cached config and missing vendor.

  IntermediatecPanel hosting · Linux VPS3 min read

• Catch-all email addresses: pros, cons and safer alternatives

  What a catch-all (default address) does, why it attracts spam and dictionary attacks, how to set or disable it in cPanel and Postfix, and better alternatives like aliases and plus addressing.

  BeginnerEmail domains2 min read

• Fix "Cannot modify header information - headers already sent"

  Fix the PHP warning 'headers already sent by output started at file:line': stray whitespace, BOM characters, echo before redirects, closing tags and plugin output.

  BeginnercPanel hosting · Linux VPS3 min read

• Fix common Composer errors on a server

  Solve frequent Composer problems: memory exhausted, PHP version or extension requirements, dependency conflicts, lock file mismatches, authentication and running as root.

  IntermediatecPanel hosting · Linux VPS3 min read

• Why forwarded email fails SPF and DMARC: SRS and ARC explained

  Why forwarding breaks SPF and sometimes DKIM, how Sender Rewriting Scheme (SRS) and ARC fix it, how to enable SRS on cPanel and Postfix, and safer alternatives to forwarding.

  AdvancedMail servers3 min read

• Debug a blank white page in PHP (display and log errors)

  Turn a blank PHP page into a readable error: enable error logging safely, find the right log file on cPanel or a VPS, and fix the usual causes like syntax errors and missing extensions.

  BeginnercPanel hosting · Linux VPS3 min read

• Stop outgoing spam from your mail server with rate limits

  How hacked mailboxes and scripts send spam from servers, how to detect it in logs and queues, and how to limit outgoing mail per user and per domain on Postfix, Exim and cPanel.

  AdvancedLinux mail servers3 min read

• Fix "Allowed memory size exhausted" PHP errors

  Understand the PHP fatal error 'Allowed memory size of X bytes exhausted', raise memory_limit on cPanel or a VPS, and find the code that uses too much memory.

  BeginnercPanel hosting · Linux VPS3 min read

• Point a domain to your hosting: nameservers vs A record

  Two ways to point a domain to MdmHost hosting: change nameservers or keep your DNS and edit A, CNAME and MX records. When to use each, step by step, and how to check it worked.

  BeginnercPanel hosting3 min read

• Convert SSL certificate formats: PEM, CRT, DER, PFX and P7B with OpenSSL

  What the common SSL certificate file formats are, how to tell them apart, and the exact OpenSSL commands to convert between PEM, DER, PFX/PKCS#12 and P7B for cPanel, Windows and other servers.

  IntermediateEveryone3 min read

Browse by topic

• Getting startedYour first hour with a new server: access, logins and basics.83 guides
• cPanelFiles, databases, email, domains and every cPanel tool, step by step.67 guides
• WHM & resellingWHM, packages, reseller accounts, WHMReseller and running a hosting brand.53 guides
• WordPressInstall, secure, speed up, migrate and fix WordPress sites.49 guides
• Email & webmailMailboxes, webmail, forwarders, spam filters and email delivery.67 guides
• DomainsRegistering, transferring and managing domains and nameservers.27 guides
• SSL certificatesFree AutoSSL, Let's Encrypt, paid certificates and HTTPS.41 guides
• CloudLinuxCloudLinux setup and use: LVE limits, CloudLinux Manager, CageFS and PHP/Node.js selectors.31 guides
• LiteSpeedLiteSpeed Web Server, LSCache and the LiteSpeed Cache plugin: install, settings and tuning.35 guides
• Imunify360Malware scanning, firewall and proactive defence with Imunify360.24 guides
• SoftaculousInstall, update, clone and back up apps with Softaculous.24 guides
• WP SquaredcPanel's WordPress platform: sites, plugins, staging and backups.9 guides
• SitePadBuild and publish websites with the SitePad builder.9 guides
• SitejetDesign, edit and publish sites with the Sitejet builder.9 guides
• WHMResellerAlpha and master resellers with WHMReseller: install, setup and use.12 guides
• VirtFusionInstall, set up and manage VirtFusion: hypervisors, packages, servers and WHMCS integration.28 guides
• VirtualizorManage your VPS with Virtualizor: power, OS reinstall, VNC, IPs and backups.44 guides
• PleskWebsites, email, databases and settings in the Plesk panel.53 guides
• DirectAdminUsers, domains, email and reseller tools in DirectAdmin.41 guides
• WHMCSBilling, automation, products and client management with WHMCS.52 guides
• Control panelscPanel & WHM, Plesk, DirectAdmin and other panels on your VPS.107 guides
• SecurityKeys, passwords, firewalls and keeping a server patched.138 guides
• Networking & DNSIP addresses, reverse DNS, ports and traffic.72 guides
• Websites & appsWeb servers, WordPress, PHP, Node.js, SSL and app hosting.83 guides
• DatabasesMySQL, MariaDB, PostgreSQL, Redis and MongoDB on a VPS.80 guides
• Billing & accountInvoices, renewals, the client area and your account.9 guides
• TroubleshootingWhen something is not working: checks and fixes.127 guides
• Linux VPSSSH, packages, services and everyday Linux administration.265 guides
• Windows VPS & RDPRemote Desktop, Windows Server settings and Admin RDP tips.73 guides
• Docker & DevOpsContainers, Git deploys, automation, monitoring and backups.82 guides