# InvalidPort (/docs/errors/chain/InvalidPort)

The `port` argument to serve\_axon or serve\_prometheus is 0, which is rejected. Check the miner or client axon configuration and serve on a non-zero port.

Declared by the `SubtensorModule` pallet; it classifies to the semantic code [`invalid_argument`](/docs/errors/invalid-argument).

## Remediation [#remediation]

Check the argument values against the operation schema

The same explanation is available in the terminal: `btcli explain InvalidPort`.