This works fine:
var resp = UrlFetchApp.fetch(\"someremotehost/SomeFile.csv\"); resp.getResponseCode(); //returns 200 resp.getContentText(); //returns the
Use Proxy. I had the same issue, where my app was on AWS ec2.
For that, I used nginx as proxy server and it worked.
That wont work because apps script executes code server side (in google servers). The only way to do this is to make an htmlService app and use ajax from the frontend.