# X_PORT_IN_USE

## Means

the dev port is taken

## Typical cause

an unrelated process holds it — usually another project's dev server; the pid and command are named when the OS will say

## Fix

`x dev --port 3001`, or kill the named pid if it is yours. The scrape port on a deployed role: `set METRICS_PORT=<free port> in this role's environment, one per role on a host`; the refusal stays, a scrape target must not move on its own

[Config and environment](/error-codes#config-and-environment)