Error while running the page

When I run the page I get this error:

Error: Can't set headers after they are sent. at SendStream.headersAlreadySent (C:\api-rest\node_modules\send\index.js:402:13) at SendStream.send (C:\api-rest\node_modules\send\index.js:625:10) at onstat (C:\api-rest\node_modules\send\index.js:737:10) at FSReqWrap.oncomplete (fs.js:123:15) Error: Can't set headers after they are sent. at SendStream.headersAlreadySent (C:\api-rest\node_modules\send\index.js:402:13) at SendStream.send (C:\api-rest\node_modules\send\index.js:625:10) at onstat (C:\api-rest\node_modules\send\index.js:737:10) at FSReqWrap.oncomplete (fs.js:123:15)

(node:11360) Warning: Possible EventEmitter memory leak detected. 11 field listeners added. Use emitter.setMaxListeners() to increase limit (node:11360) Warning: Possible EventEmitter memory leak detected. 11 file listeners added. Use emitter.setMaxListeners() to increase limit (node:11360) Warning: Possible EventEmitter memory leak detected. 11 error listeners added. Use emitter.setMaxListeners() to increase limit (node:11360) Warning: Possible EventEmitter memory leak detected. 11 end listeners added. Use emitter.setMaxListeners() to increase limit

this is my code:

app.get('/principal', (req, res, err, next) => {    
Noticias.find({}, (e, noticias) => {
    noticias.forEach(function (element) {
        var myStrin = '' + element.Contenido;
        myStrin = myStrin.slice(0, 100);
        element.Contenido = myStrin + '...';
    }, this);
    if (e) {
        console.log(e);
    } else if (!noticias) {
        console.log("Error, el archivo no existe")
    } else {
        res.render('index', { noticias, title: "ICMA", uno: "select", dos: "", tres: "", cuatro: "", cinco: "" })
    }

})

});

via Martínez Oscar