mongoose never stops loading - node.js

Question

I am on windows. The local database is running fine, I can write to and find collections with the mongo command line tool. The local nodejs is running fine as well. When I remove my mongoose code, I can reach my endpoints.
When I start the node server with the mongoose code, I get this message:
23:05:57 web.1 | started with pid 20860
23:05:58 web.1 | { [Error: Cannot find module '../build/Release/bson'] code: 'MODULE_NOT_FOUND' }
23:05:58 web.1 | js-bson: Failed to load c++ bson extension, using pure JS version
23:05:58 web.1 | Node app is running at localhost:5000
The server starts, although the error is worrisome (have tried to fix it for a good while, no luck yet), but it doesn't seem like a fatal error.
When I try to access one of my endpoints, either through Postman API, the browser or my application, it tries to connect forever. I can also see in mongo that a connection to the db never is made.
This is the code I have right now:
var express = require('express');
var app = express();
var mongoose = require('mongoose');
app.set('port', (process.env.PORT || 5000));
app.use(express.static(__dirname + '/public'));
mongoose.connection.on("open", function(ref) {
console.log("Connected to mongo server.");
return start_up();
});
mongoose.connection.on("error", function(err) {
console.log("Could not connect to mongo server!");
return console.log(err);
});
mongoose.connect("mongodb://localhost/test");
app.listen(app.get('port'), function() {
console.log("Node app is running at localhost:" + app.get('port'));
});
app.get('/', function(request, response) {
response.send("Hello StackOverflow");
});
I've been sitting quite a few hours over the last three days trying to make it work, feels like I've been through every remotely relevant google search at this point. Hope you can help me out. :)
EDIT: If I go with mongoose version 3.8.3. The MODULE_NOT_FOUND error disappears. But it doesn't fix the never ending load.