Error map

nginx: invalid PID number in nginx.pid Nginx: nginx: [error] invalid PID number "" in "/run/nginx.pid" (when running nginx -s reload)

Nginx / Apache · layer 3, Edge & web server

Centre: this error. First ring: errors it is linked with (7). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.

2 · Network 3 · Edge & web server 4 · Application & API 6 · Platform & cloud

Directly related (7)

Job for x.service failedLinux

Job for nginx.service failed because the control process exited with error code

systemd tried to start the service, but its start command failed. The real reason is in the service’s status/journal.

AH00112: DocumentRoot does not existNginx / Apache

Apache: AH00112: Warning: DocumentRoot [/var/www/example.com/public_html] does not exist

A virtual host points to a directory that doesn't exist.

AH00072: make_sock: could not bind to address 0.0.0.0:80Nginx / Apache

Apache: (98)Address already in use: AH00072: make_sock: could not bind to address [::]:80 / AH00015: Unable to open logs

Another process (Nginx, another Apache, Skype/IIS-like service) already listens on the port Apache wants.

nginx: [emerg] unexpected end of file, expecting ";" or "}"Nginx / Apache

Nginx: nginx: [emerg] unexpected end of file, expecting ";" or "}" in /etc/nginx/conf.d/site.conf:42

The config ends while a block or directive is still open — a missing `}` or `;`.

AH00015: Unable to open logsNginx / Apache

Apache: AH00091: apache2: could not open error log file /var/log/apache2/error.log. AH00015: Unable to open logs (Permission denied)

Apache can't open its log files — permissions, a missing directory or disk problems.

apache2.service: Failed with result 'exit-code'Nginx / Apache

systemd: apache2.service: Main process exited, code=exited, status=1/FAILURE — Job for apache2.service failed because the control process exited with error code

systemd couldn't start Apache — the real error is in the journal or `apachectl configtest`.

nginx: bind() to 0.0.0.0:80 failed (13: Permission denied)Nginx / Apache

Nginx: nginx: [emerg] bind() to 0.0.0.0:80 failed (13: Permission denied)

Nginx isn't allowed to bind that port — a privileged port as non-root, or SELinux restricts it.

Two steps away (21)

provided port is not in the valid rangeKubernetes

spec.ports[0].nodePort: Invalid value: 80: provided port is not in the valid range. The range of valid ports is 30000-32767

A NodePort Service asked for a port outside the cluster’s NodePort range (default 30000–32767).

bind() failed (98: Address already in use)Linux

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)

Nginx (or another server) can’t listen on the port because another process already holds it — often Apache, another Nginx, or a s…

Unit not foundLinux

Failed to start x.service: Unit x.service not found

systemd has no unit with that name — the package isn’t installed, the name differs on this distro, or a new unit file wasn’t load…

nodemon crashedNode.js

[nodemon] app crashed - waiting for file changes before starting...

Your app threw an error on startup; nodemon is waiting for a file change to retry.

AH00558Nginx / Apache

Apache: AH00558: apache2: Could not reliably determine the server's fully qualified domain name

A harmless startup warning: Apache has no global ServerName, so it guessed one from the host’s IP.

Welcome to nginx! shown instead of my siteNginx / Apache

Browser: Welcome to nginx! If you see this page, the nginx web server is successfully installed and working

Requests are served by the default server block, not your site's block.

EADDRINUSENode.js

Error: listen EADDRINUSE: address already in use :::3000

Another process is already listening on that port.

listen EACCESNode.js

Error: listen EACCES: permission denied 0.0.0.0:80

Node isn’t allowed to bind that port — ports below 1024 need root on Linux/macOS, and some Windows ports are reserved.

AH00526: Syntax error on line of apache configNginx / Apache

Apache: AH00526: Syntax error on line 12 of /etc/apache2/sites-enabled/site.conf: Invalid command 'Foo', perhaps misspelled or defined by a module not included in the server configuration

Apache's config has a syntax problem or a directive from a module that isn't loaded.

Parse errorPHP

PHP Parse error: syntax error, unexpected …

PHP can’t parse the file because of a syntax mistake — the real error is often on the line before the one reported.

nginx: [emerg] unknown directiveNginx / Apache

Nginx: nginx: [emerg] unknown directive "x" in /etc/nginx/sites-enabled/x:12 — configuration file test failed

Nginx found a directive it doesn’t know — a typo, a missing semicolon on the previous line, a directive from a module that isn’t…

nginx: directive is not terminated by ";"Nginx / Apache

Nginx: nginx: [emerg] directive "proxy_pass" is not terminated by ";" in /etc/nginx/sites-enabled/app:15

A directive's arguments run into the next line because the `;` is missing (or a quote is unbalanced).

500HTTP

HTTP 500 Internal Server Error

The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.

499HTTP

HTTP 499 Client Closed Request (Nginx)

Nginx-specific code logged when the client disconnected before the server finished responding.

SSLCertificateFile: file does not existSSL / TLS

Apache: AH02240: Server should be SSL-aware but has no certificate configured / SSLCertificateFile: file '/etc/ssl/x.crt' does not exist or is empty

Apache cannot find the certificate or key file named in its configuration, or `SSLEngine on` is set without any certificate.

System has not been booted with systemdLinux

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