98: Unknown error

Please use this template for troubleshooting questions.

My issue:

Frequently crashing, hardly runs more than 12hrs without any load. Can’t find the exact issue, nginx was functioning properly non stop for years.

nginx is the frontend login page for application running in tomcat9, tomcat9 and application are still running. whenever nginx crash, need to manually start the service.

This server do not have any other applications that require port 80 and 443.

systemctl status nginx.service
× nginx.service - A high performance web server and a reverse proxy server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Tue 2026-03-24 03:58:05 IST; 9h ago
Docs: man:nginx(8)
Process: 15027 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
Process: 15028 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=1/FAILURE)
CPU: 41ms

Mar 24 03:58:04  nginx[15028]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Unknown error)
Mar 24 03:58:04  nginx[15028]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Unknown error)
Mar 24 03:58:04  nginx[15028]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Unknown error)
Mar 24 03:58:04  nginx[15028]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Unknown error)
Mar 24 03:58:05  nginx[15028]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Unknown error)
Mar 24 03:58:05  nginx[15028]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Unknown error)
Mar 24 03:58:05  nginx[15028]: nginx: [emerg] still could not bind()
Mar 24 03:58:05  systemd[1]: nginx.service: Control process exited, code=exited, status=1/FAILURE
Mar 24 03:58:05  systemd[1]: nginx.service: Failed with result ‘exit-code’.
Mar 24 03:58:05  systemd[1]: Failed to start A high performance web server and a reverse proxy server.

How I encountered the problem:

Solutions I’ve tried:

ran ubuntu updates, including security.

Version of NGINX or NGINX adjacent software (e.g. NGINX Gateway Fabric):

nginx/1.18.0 (Ubuntu)

Deployment environment:

on-prem, production.

Minimal NGINX config to reproduce your issue (preferably running on https://tech-playground.com/playgrounds/nginx for ease of debugging, and if not as a code block): (Tip → Run nginx -T to print your entire NGINX config to your terminal.)

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
# configuration file /etc/nginx/nginx.conf:
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
	worker_connections 768;
	# multi_accept on;
}

http {

	##
	# Basic Settings
	##
client_max_body_size 300m;
	sendfile on;
	tcp_nopush on;
	types_hash_max_size 2048;
	# server_tokens off;

	# server_names_hash_bucket_size 64;
	# server_name_in_redirect off;

	include /etc/nginx/mime.types;
	default_type application/octet-stream;

	##
	# SSL Settings
	##

	ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
	ssl_prefer_server_ciphers on;

	##
	# Logging Settings
	##

	access_log /var/log/nginx/access.log;
	error_log /var/log/nginx/error.log;

	##
	# Gzip Settings
	##

	gzip on;

	# gzip_vary on;
	# gzip_proxied any;
	# gzip_comp_level 6;
	# gzip_buffers 16 8k;
	# gzip_http_version 1.1;
	# gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

	##
	# Virtual Host Configs
	##

	include /etc/nginx/conf.d/*.conf;
	include /etc/nginx/sites-enabled/*;
}


#mail {
#	# See sample authentication script at:
#	# http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#	# auth_http localhost/auth.php;
#	# pop3_capabilities "TOP" "USER";
#	# imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#	server {
#		listen     localhost:110;
#		protocol   pop3;
#		proxy      on;
#	}
#
#	server {
#		listen     localhost:143;
#		protocol   imap;
#		proxy      on;
#	}
#}

# configuration file /etc/nginx/modules-enabled/50-mod-http-geoip2.conf:
load_module modules/ngx_http_geoip2_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-http-image-filter.conf:
load_module modules/ngx_http_image_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-http-xslt-filter.conf:
load_module modules/ngx_http_xslt_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-mail.conf:
load_module modules/ngx_mail_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-stream.conf:
load_module modules/ngx_stream_module.so;

# configuration file /etc/nginx/modules-enabled/70-mod-stream-geoip2.conf:
load_module modules/ngx_stream_geoip2_module.so;

# configuration file /etc/nginx/mime.types:

types {
    text/html                             html htm shtml;
    text/css                              css;
    text/xml                              xml;
    image/gif                             gif;
    image/jpeg                            jpeg jpg;
    application/javascript                js;
    application/atom+xml                  atom;
    application/rss+xml                   rss;

    text/mathml                           mml;
    text/plain                            txt;
    text/vnd.sun.j2me.app-descriptor      jad;
    text/vnd.wap.wml                      wml;
    text/x-component                      htc;

    image/png                             png;
    image/tiff                            tif tiff;
    image/vnd.wap.wbmp                    wbmp;
    image/x-icon                          ico;
    image/x-jng                           jng;
    image/x-ms-bmp                        bmp;
    image/svg+xml                         svg svgz;
    image/webp                            webp;

    application/font-woff                 woff;
    application/java-archive              jar war ear;
    application/json                      json;
    application/mac-binhex40              hqx;
    application/msword                    doc;
    application/pdf                       pdf;
    application/postscript                ps eps ai;
    application/rtf                       rtf;
    application/vnd.apple.mpegurl         m3u8;
    application/vnd.ms-excel              xls;
    application/vnd.ms-fontobject         eot;
    application/vnd.ms-powerpoint         ppt;
    application/vnd.wap.wmlc              wmlc;
    application/vnd.google-earth.kml+xml  kml;
    application/vnd.google-earth.kmz      kmz;
    application/x-7z-compressed           7z;
    application/x-cocoa                   cco;
    application/x-java-archive-diff       jardiff;
    application/x-java-jnlp-file          jnlp;
    application/x-makeself                run;
    application/x-perl                    pl pm;
    application/x-pilot                   prc pdb;
    application/x-rar-compressed          rar;
    application/x-redhat-package-manager  rpm;
    application/x-sea                     sea;
    application/x-shockwave-flash         swf;
    application/x-stuffit                 sit;
    application/x-tcl                     tcl tk;
    application/x-x509-ca-cert            der pem crt;
    application/x-xpinstall               xpi;
    application/xhtml+xml                 xhtml;
    application/xspf+xml                  xspf;
    application/zip                       zip;

    application/octet-stream              bin exe dll;
    application/octet-stream              deb;
    application/octet-stream              dmg;
    application/octet-stream              iso img;
    application/octet-stream              msi msp msm;

    application/vnd.openxmlformats-officedocument.wordprocessingml.document    docx;
    application/vnd.openxmlformats-officedocument.spreadsheetml.sheet          xlsx;
    application/vnd.openxmlformats-officedocument.presentationml.presentation  pptx;

    audio/midi                            mid midi kar;
    audio/mpeg                            mp3;
    audio/ogg                             ogg;
    audio/x-m4a                           m4a;
    audio/x-realaudio                     ra;

    video/3gpp                            3gpp 3gp;
    video/mp2t                            ts;
    video/mp4                             mp4;
    video/mpeg                            mpeg mpg;
    video/quicktime                       mov;
    video/webm                            webm;
    video/x-flv                           flv;
    video/x-m4v                           m4v;
    video/x-mng                           mng;
    video/x-ms-asf                        asx asf;
    video/x-ms-wmv                        wmv;
    video/x-msvideo                       avi;
}

# configuration file /etc/nginx/sites-enabled/<removed>.conf:
server {
    root /var/www/html;
    index index.nginx-debian.html;
    server_name <removed>;
    location /jump/ {
        proxy_pass http://localhost:8080;
        proxy_buffering off;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $http_connection;
client_max_body_size 1g;
        access_log off;
    }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/<removed>-0001/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/<removed>-0001/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot


    add_header Strict-Transport-Security "max-age=31536000" always; # managed by Certbot

}
server {
    if ($host = <removed>) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    listen 80 default_server;
    root /var/www/html;
    index index.nginx-debian.html;
    server_name <removed>;
    location /jump/ {
        proxy_pass http://localhost:8080;
        proxy_buffering off;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $http_connection;
client_max_body_size 1g;
        access_log off;
    }

}

# configuration file /etc/letsencrypt/options-ssl-nginx.conf:
# This file contains important security parameters. If you modify this file
# manually, Certbot will be unable to automatically provide future security
# updates. Instead, Certbot will print and log an error message with a path to
# the up-to-date file that you will need to refer to when manually updating
# this file. Contents are based on https://ssl-config.mozilla.org

ssl_session_cache shared:le_nginx_SSL:10m;
ssl_session_timeout 1440m;
ssl_session_tickets off;

ssl_protocols TLSv1.2 TLSv1.3;
ssl_prefer_server_ciphers off;

ssl_ciphers "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384";


NGINX access/error log: (Tip → You can usually find the logs in the /var/log/nginx directory.)

error.log

2026/03/24 03:57:23 [notice] 14991#14991: signal process started
2026/03/24 03:57:23 [error] 14991#14991: invalid PID number "" in "/run/nginx.pid"
2026/03/24 03:57:35 [notice] 15000#15000: signal process started
2026/03/24 03:57:47 [notice] 15008#15008: signal process started
2026/03/24 03:58:01 [notice] 15014#15014: signal process started
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:443 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:80 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:443 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:80 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:443 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:80 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:443 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:80 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:443 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: bind() to 0.0.0.0:80 failed (98: Unknown error)
2026/03/24 03:58:03 [emerg] 15028#15028: still could not bind()
2026/03/24 03:58:06 [alert] 14993#14993: unlink() "/run/nginx.pid" failed (2: No such file or directory)

access.log is empty.

Any help to resolve this appreciated, Thanks.

2 Likes

It smells like something is already bound to 0.0.0.0:80/443

Things to check

  1. Before attempting to start nginx, check there is nothing already bound to that address/ports (use something like ss -tnl)

  2. Make sure your nginx config isn’t loading duplicate server sections with the same listen directives.

  3. Your systemd unit file seems a little odd w.r.t the ExecStartPre. The Fedora nginx systemd unit file has

ExecStartPre=/usr/bin/rm -f /run/nginx.pid
ExecStartPre=/usr/sbin/nginx -t
ExecStart=/usr/sbin/nginx

Maybe your ExecStartPre is interfering with the ExecStart

1 Like

Thanks for responding, it crashed again !!!.

nothing is bound to 80/443.

1,

~$ sudo systemctl status nginx.service 
× nginx.service - A high performance web server and a reverse proxy server
     Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Wed 2026-03-25 06:52:03 IST; 2h 10min ago
       Docs: man:nginx(8)
    Process: 52191 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
    Process: 52192 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=1/FAILURE)
        CPU: 37ms
                                                                         
~$ ss -tnl
State   Recv-Q   Send-Q     Local Address:Port      Peer Address:Port  Process  
LISTEN  0        4096       127.0.0.53%lo:53             0.0.0.0:*              
LISTEN  0        128              0.0.0.0:22             0.0.0.0:*              
LISTEN  0        5                0.0.0.0:4822           0.0.0.0:*              
LISTEN  0        5              127.0.0.1:23578          0.0.0.0:*              
LISTEN  0        80             127.0.0.1:3306           0.0.0.0:*              
LISTEN  0        128            127.0.0.1:5000           0.0.0.0:*              
LISTEN  0        128                 [::]:22                [::]:*              
LISTEN  0        100                    *:8080                 *:*              
~$ 
~$ sudo lsof -i:443
~$
~$ sudo lsof -i:80
~$

2, only this particular site / application is being run.

3, would running nginix as SysVinit or as process would resolve this issue ?.

Thanks.

Thanks for responding, it crashed again !!!.

I don’t think it’s crashing, just failing to start…

OK, so nothing already on ports 80/443

would running nginix as SysVinit or as process would resolve this issue ?

Actually you could simply try running like

# nginx -c /path/to/config

Just to see if that successfully starts.

1 Like

nginx crashes when running as SysV or systemd !!!.

Its been running as “process” for the past 4days without any issue, there is not a single clue what other process causes it to crash.