# 40010: Invalid channel name

Identifier: `invalid_channel_name`



The channel name in the request was not valid, for example because it was empty, contained characters that are not permitted, or used an unknown square-bracketed prefix.

## What you should do

Use a valid channel name and retry. Names must not be empty, must not start with `[` or `:`, and must not contain newline characters. See the [channel naming rules](https://ably.com/docs/channels.md) for the full set.

## Why it happens

The channel name in the request broke one of the naming rules, or a square-bracketed qualifier was malformed. This includes an empty name, a disallowed leading character, an unsupported qualifier or parameter in the `[...]` prefix, or an unparseable channel key.

## What you'll see

The error is reported with code 40010 and HTTP status 400. The message is typically `invalid channel name: ...`, or names the specific problem such as `Invalid qualifier in channelId; ...`.