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Error starting userland proxy: listen tcp 0.0.0.0:8080: bind: address already in use

The port you're trying to publish is already being used by another process or a Docker container. Docker can't bind to the port because the OS won't allow two processes to listen on the same address and port at the same time.

Common causes

  • Another Docker container is already published on the same port — check with docker ps
  • A local service (a dev server, database, or another app) is using the port
  • A previous container wasn't properly stopped and is still holding the port
  • A system service (like a web server on port 80/443) is running on that port

How to fix it

  1. Find what's using the port: lsof -i :8080 (Mac/Linux) or netstat -ano | findstr 8080 (Windows)
  2. Stop the conflicting Docker container: docker ps, then docker stop CONTAINER_ID
  3. Map to a different host port: docker run -p 8081:8080 myimage (8081 on host → 8080 in container)
  4. Stop the conflicting local service before starting Docker

Example

$ docker run -p 8080:8080 myapp docker: Error response from daemon: driver failed programming external connectivity on endpoint myapp: Error starting userland proxy: listen tcp4 0.0.0.0:8080: bind: address already in use.

Another process is already listening on port 8080 on the host

Related Docker Errors

Cannot connect to Docker daemonPermission denied connecting to Docker socketDocker daemon not running on this hostImage not found or pull access deniedImage manifest not found (tag doesn't exist)

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