Error map
port 5432 in use LOG: could not bind IPv4 address "0.0.0.0": Address already in use — Is another postmaster already running on port 5432?
PostgreSQL · layer 5, Data
Centre: this error. First ring: errors it is linked with (12). 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.
Directly related (12)
[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.
HTTP Error 500.30 - ASP.NET Core app failed to start
IIS/Azure’s ASP.NET Core Module launched your app but it crashed during startup.
java.lang.ExceptionInInitializerError
A static initializer (static block or static field) threw an exception while the class was loading.
Docker: Bind for 0.0.0.0:80 failed: port is already allocated
Another container or host process already publishes that host port.
Error: listen EADDRINUSE: address already in use :::3000
Another process is already listening on that port.
driver failed programming external connectivity on endpoint: iptables: No chain/target/match by that name
Docker’s iptables rules were wiped (firewalld/ufw reload, iptables flush) while Docker was running, so it can’t publish ports.
Job for mysql.service failed because the control process exited with error code
The MySQL/MariaDB service failed to start — the real reason is in the MySQL error log.
ERROR: database "x" is being accessed by other users — There is 1 other session using the database.
DROP/RENAME DATABASE can’t run while other sessions are connected.
FATAL: lock file "postmaster.pid" already exists — Is another postmaster running in data directory?
PostgreSQL won’t start because a stale postmaster.pid file remains (or another instance really is running).
FATAL: the database system is starting up
PostgreSQL is still starting (or recovering) and not accepting connections yet.
System.IO.IOException: Failed to bind to address http://127.0.0.1:5000: address already in use
Kestrel can’t listen because another process (often a previous run of the same app) uses the port.
Web server failed to start. Port 8080 was already in use.
Spring Boot couldn’t bind its embedded server port because another process uses it.
Two steps away (30)
Error: Cannot find module 'x' (MODULE_NOT_FOUND)
Node can’t resolve the module path — the package isn’t installed, or a relative path/extension is wrong.
npm ERR! could not determine executable to run
npx couldn’t find a binary to run for that package.
pg_dump: error: aborting because of server version mismatch
Your pg_dump client is older than the server you’re dumping.
HTTP 500 Internal Server Error
The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.
Azure App Service: ":( Application Error" / container didn’t respond to HTTP pings
App Service started your app but it crashed or never listened on the expected port.
InvalidOperationException: Unable to resolve service for type 'X' while attempting to activate 'Y'
ASP.NET Core’s dependency injection container can’t build Y because one of its constructor dependencies (X) was never registered.
Docker container exits immediately (Exited (0) / Exited (1) right after start)
The container started and its main process finished at once, so the container stopped — Docker containers only live as long as PI…
Docker container keeps restarting (Restarting (1) x seconds ago)
The container crashes on start and its restart policy (always/unless-stopped/on-failure) starts it again in a loop.
Pod status Init:CrashLoopBackOff / Init:Error
An init container keeps failing, so the pod’s main containers never start.
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
The docker CLI can’t talk to the Docker engine — it isn’t running, or your user can’t access the socket.
Conflict. The container name "/x" is already in use by container …
A container (running or stopped) already has that name; Docker won’t create a second one with the same name.
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.
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
npm ERR! code ELIFECYCLE / Command failed with exit code 1
An npm script (build, start, test, postinstall) exited with an error. ELIFECYCLE is only the wrapper — the real error is printed…
Error: write EPIPE
Node wrote to a pipe or socket whose other end was already closed.
Cloudflare Error 1020: Access Denied
A Cloudflare firewall/WAF custom rule blocked the request — the visitor’s IP, country, user agent or request pattern matched a bl…
OSError: [Errno 98] Address already in use
The port your server wants to bind is already taken by another process.
ECS task stopped: CannotPullContainerError: pull image manifest has been retried ... / ref pull has been retried
The ECS task couldn’t pull its image — no network route to the registry, missing ECR permissions, or a wrong image tag.
MySQL ERROR 2002 (HY000): Can't connect to local MySQL server through socket
The client couldn’t reach the MySQL server — it isn’t running, or the client is looking for the socket/port in the wrong place.
PostgreSQL: ERROR: column "x" does not exist
PostgreSQL can’t find the column — a missing migration, a case-sensitive quoted name, or a string literal written in double quote…
ERROR: canceling statement due to statement timeout
A query ran longer than statement_timeout and PostgreSQL cancelled it.
ERROR: column "x" of relation "y" already exists
ALTER TABLE ADD COLUMN for a column that’s already there.
FATAL: data directory "/var/lib/postgresql/data" has invalid permissions — Permissions should be u=rwx (0700) or u=rwx,g=rx (0750).
PostgreSQL refuses to start because the data directory is too open or owned by the wrong user.
FATAL: database files are incompatible with server — The data directory was initialized by PostgreSQL version 15, which is not compatible with this version 16
A newer (or older) PostgreSQL major version was started on an existing data directory.
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…
Unable to configure HTTPS endpoint. No server certificate was specified, and the default developer certificate could not be found or is out of date
Kestrel was told to listen on HTTPS but has no certificate — the ASP.NET Core dev certificate is missing/expired, or production d…
HttpRequestException: No connection could be made because the target machine actively refused it (localhost:5001)
Nothing is listening on the host/port the client called — the API isn’t running, uses another port, or the container/network addr…
UnsatisfiedDependencyException / NoSuchBeanDefinitionException: No qualifying bean of type 'X' available
Spring couldn’t find (or choose) a bean to inject.
The dependencies of some of the beans in the application context form a cycle
Two or more Spring beans depend on each other through constructors, and Spring Boot 2.6+ forbids cycles by default.
Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.
Spring Boot found JDBC/JPA on the classpath but no database URL.
Map another error
Popular: 500403400ORA-009331064Critical errorFileNotFoundException assemblyTypeError