AMP Access Control Allow Source Origin header Issue

Question

How can I resolve the error below;

Failed to load resource: the server responded with a status of 500 (Internal Server Error) cdn.ampproject.org/v0.

Answer 1

Although OP uses PHP, I'm posting here for my javascript peeps.

For node express server, you can use amp-toolbox-cors, which provides middleware.

const express = require('express');
const ampCors = require('amp-toolbox-cors');

const app = express();

// That's it!
app.use(ampCors());
...

By default, the AMP CORS middleware will only allow requests from AMP Caches listed on https://cdn.ampproject.org/caches.json (with the addition of bing-amp.com).

All other origins will receive a 403 response.

So for localhost or dev testing, you guys will probably want to also add the following:

app.use(ampCors({
  verifyOrigin: false
}));

For those who want to take a deeper dive, here's a link to offical docs on how to comply with AMP CORS.