I am running server in nodejs, while executing the code of server i am getting an error as "(node:7692) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): Error: Request failed with status code 400 (node:7692) 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".

this is my serverrender.js code

import axios from 'axios';
import config from './config';

axios.get('${config.serverUrl/api/contests')
.then(resp=>{
    console.log(resp.data);
});

this is my srver.js code

    import config from './config';
    import apiRouter from './api';
    import express from 'express';
    import path from 'path';
    import sassMiddleware from 'node-sass-middleware';

    import './serverRender';
    const server=express();
    server.set('view engine','ejs');

    server.use(sassMiddleware({
        src:path.join(__dirname,'sass'),
        dest:path.join(__dirname,'public')
    }));

    server.get('/',(req,res)=>{

        res.render('index',{
            content:"... "
        });


});
server.use(express.static('public'));

server.use('/api',apiRouter);

server.listen(config.port, config.host, () =>{
    console.info('express listening on port ',config.port);
});