# 90010: Too many channels

Identifier: `too_many_channels`



An operation was rejected because it would exceed the maximum number of channels permitted, either the channels attached to a single connection or those included in a single batch request.

## What you should do

If you hit the per-connection limit, detach channels the connection no longer needs; the usual cause is channels that are attached and then never explicitly detached. If you hit it on a batch publish or batch presence request, reduce the number of channels included in a single request. If your use case genuinely needs more, [contact Ably support](https://ably.com/support) to raise the limit.

## Why it happens

The operation would exceed a maximum number of channels. This applies in two places: the number of channels attached to a single connection, and the number of channels included in a single batch publish or batch presence request. Both limits are set by the account.

## What you'll see

The error is reported with code 90010 and HTTP status 400. The messages include `Maximum number of channels per connection (<n>) exceeded`, `Max number of channels permitted in a single bulk publish request (<n>) exceeded`, and `Max number of channels permitted in a single batch presence request (<n>) exceeded`.