40143: Token not recognized

A connection or request was rejected because Ably could not find a record of the token presented. Ably stores a record of certain tokens only while they remain valid, so this often means the token had already expired.

What you should do

Usually nothing, when the client is configured to renew its own tokens. Such a client obtains a replacement when a token is rejected and recovers without intervention, so a 40143 that clears on its own needs no action. In practice it is often indistinguishable from ordinary token expiry.

Act when it persists or reaches your application. The common cause is a client running on an expired token without renewing it, so confirm an authUrl or authCallback is configured so the client can obtain fresh tokens.

Why it happens

Ably keeps a stored record of some tokens, and only for as long as they remain valid. This error means a token of that kind was presented but no matching record was found, most often because it had expired and its record had already been removed. That is why such a token is reported as unrecognized rather than expired (40142).

What you'll see

The error is reported with code 40143 and HTTP status 401. The message is token unrecognized; some paths include the token identifier, as Token unrecognized: <id>.