nuxt asyncData axios 503

Question

when I use $axios.$get in asyncData,

async asyncData({ $axios }) {
        const { list } = await $axios.$get('http://localhost:3000/api/list')
        return { list }
}

ubuntu terminal always throw error like:

(node:9628) UnhandledPromiseRejectionWarning: Error: Request failed with status code 503
at IncomingMessage.emit (events.js:228:7)
    at IncomingMessage.EventEmitter.emit (domain.js:475:20)
    at endReadableNT (_stream_readable.js:1185:12)
    at processTicksAndRejections (internal/process/task_queues.js:81:21)
(node:9628) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 6)
(node:9628) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

but when I use the terminal in the vscode, error disappeared. I'm confused. :(