40033: Operation canceled

An operation was stopped before completing, so its result was discarded. This usually happens when the connection or request that triggered the operation ends first.

What you should do

If you stopped the operation yourself, by closing the connection or abandoning the request before it returned, this is expected and there is nothing to do. Otherwise it did not complete, so if its result mattered, issue it again; it is not retried automatically.

Why it happens

The operation, such as publishing a message, was stopped part-way rather than rejected on its own merits. The usual cause is that the connection or request driving the operation ended first: the connection closed, or the client stopped waiting for the response. Ably stopped processing at that point.

What you'll see

The error is reported with code 40033 and HTTP status 400. The message is operation canceled; the spelling operation canceled appears on some paths.