Error map
Port 5000/7000 already in use (AirPlay Receiver) macOS: Address already in use — Port 5000 is in use by ControlCenter (AirPlay Receiver)
macOS · layer 6, Platform & cloud
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)
OSError: [Errno 98] Address already in use
The port your server wants to bind is already taken by another process.
Docker: Bind for 0.0.0.0:80 failed: port is already allocated
Another container or host process already publishes that host 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.
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…
Homebrew: Error: Permission denied @ dir_s_mkdir - /usr/local/Cellar / /opt/homebrew is not writable
Homebrew can't write to its prefix because the folders are owned by another user or root.
macOS: Bootstrap failed: 5: Input/output error / launchctl load: Load failed: 5: Input/output error
launchd couldn't load a LaunchAgent/Daemon plist — it's invalid, already loaded, or has the wrong ownership/permissions.
Go: listen tcp :8080: bind: address already in use
The port your Go server wants is already taken by another process (or a previous instance of your app).
Homebrew: Error: No available formula with the name "x". Did you mean ...?
Homebrew can't find a formula or cask with that name in the taps it knows.
Homebrew: Error: Your Command Line Tools (CLT) are too outdated. Update them from Software Update / Please update to the latest macOS
Homebrew requires a newer Command Line Tools version than the one installed.
Homebrew: Error: It seems there is already an App at '/Applications/Chrome.app'
A cask install failed because the app is already installed manually (or a leftover exists).
macOS (Apple Silicon): zsh: bad CPU type in executable: ./tool
You ran an Intel (x86_64) program on an Apple Silicon Mac without Rosetta 2 (or an arm64 binary on an Intel Mac).
Rails/Puma: Errno::EADDRINUSE: Address already in use - bind(2) for "0.0.0.0" port 3000
Another process already listens on the port Puma wants.
Two steps away (36)
Error: listen EADDRINUSE: address already in use :::3000
Another process is already listening on that 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.
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.
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.
npm ERR! code EROFS — EROFS: read-only file system
npm tried to write to a read-only location (read-only container filesystem, mounted volume, or system path).
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…
LOG: could not bind IPv4 address "0.0.0.0": Address already in use — Is another postmaster already running on port 5432?
Another process (often a second PostgreSQL install or a container) already listens on 5432.
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.
HTTP 403 Forbidden
The server understood the request but refuses to authorize it — you (or the server process) are not allowed to access this resour…
Nginx 444 No Response (connection closed without response)
An Nginx-specific code: the server deliberately closed the connection without sending anything — a rule is dropping the request.
Nginx 400: The SSL certificate error (495 / 496 client certificate)
Nginx rejected the request because the client certificate was invalid (495) or missing (496) on a site that requires mutual TLS.
npm ERR! code EACCES — permission denied
npm can’t write to a directory — usually global installs into a root-owned folder.
user is not in the sudoers file. This incident will be reported.
Your account isn’t allowed to use sudo.
npm update check failed — Try running with sudo or get access to the local update config store
npm’s update notifier couldn’t write its config — usually root-owned files in ~/.config from a past sudo npm.
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.
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…
systemd: Start request repeated too quickly / service hit its start limit
The service crashed and restarted several times in a short period, so systemd stopped trying (StartLimitBurst).
Error response from daemon: network X not found
The container or Compose project refers to a Docker network that doesn’t exist (any more).
Error response from daemon: Pool overlaps with other one on this address space
Docker tried to create a network whose subnet clashes with an existing Docker network (or a VPN/host route).
Go: cannot assign to struct field users["bob"].Age in map
Map values are not addressable, so you cannot modify a field of a struct stored directly in a map.
macOS: zsh: command not found: brew (Homebrew not on PATH on Apple Silicon)
Homebrew is installed in /opt/homebrew on Apple Silicon Macs, which isn’t on PATH until you add its shellenv line.
Homebrew: Error: Failure while executing; `git fetch --force origin` exited with 128 / fatal: not in a git directory
`brew update` couldn't fetch the Homebrew repositories — network, a broken git state or safe.directory problems.
zsh: compinit: insecure directories, run compaudit for list. Ignore insecure directories and continue [y] or abort compinit [n]?
zsh refuses to load completions from directories owned by another user or writable by others.
gyp: No Xcode or CLT version detected!
node-gyp on macOS can’t find the Xcode Command Line Tools to compile native modules.
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun
The Xcode Command Line Tools are missing or broken — typical right after a macOS update.
macOS: Agreeing to the Xcode/iOS license requires admin privileges, please run "sudo xcodebuild -license" and then retry this command
A new Xcode (or CLT) version needs its license accepted before command-line tools run.
macOS: xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance
A command needs the full Xcode app, but `xcode-select` points to the Command Line Tools only.
macOS: “app” cannot be opened because Apple cannot check it for malicious software / Apple could not verify “app” is free of malware that may harm your Mac
Gatekeeper blocked an app that is not notarized by Apple.
macOS: “app” can’t be opened because it is from an unidentified developer
Gatekeeper refuses to open an app that isn't signed with a registered Developer ID.
exec /usr/local/bin/docker-entrypoint.sh: exec format error
The container tried to run a binary built for a different CPU architecture (arm64 vs amd64) — or a script with a broken shebang /…
zsh: no matches found: package[extra] (glob pattern not matched)
zsh treats `[ ]`, `*` or `?` in an argument as a glob and fails when nothing matches, unlike bash which passes the text through.
macOS: dlopen: mach-o file, but is an incompatible architecture (have 'x86_64', need 'arm64')
A library or binary was built for a different CPU architecture than the process loading it.
Rails: ActiveRecord::ConnectionNotEstablished: No connection pool for 'ActiveRecord::Base' found
ActiveRecord has no database connection configured or established for this process.
Rails: ActiveRecord::IrreversibleMigration — This migration uses remove_column without a type; db:rollback can't reverse it
`rails db:rollback` can't undo the migration because it contains an operation Rails can't invert.
Rails: ActiveRecord::Deadlocked: PG::TRDeadlockDetected: ERROR: deadlock detected
Two transactions locked rows in opposite orders, so PostgreSQL aborted one.
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