This error code usually indicates that the app you are accessing belongs to an account that has been manually disabled by Ably.
Alternatively, this error code may also appear for if you are accessing an app that belongs to a dedicated cluster, via an incorrect URL. Our Enterprise customers who have chosen to have their own private cluster are provided with custom environment endpoints. If a request arrives at the default global endpoints, the account the app belongs to in the global scope may be disabled, and as such, this error message may be shown to users. We recommend you check your custom environment settings for all connecting clients if this applies.