Timeout in 20s when process async function at server side plugin action

When I make some async call in context.async function, the server-side log always shows Workflow error - Sorry, we ran into a temporary bug and can't complete your request. We'll fix it as soon as we can; please try again in a bit! in 20 seconds, but my function only takes about 10 seconds in the local environment, not sure whether the server error is triggered by timeout error.