This appears to be a bug with Gutenberg. It has to do with the overflow of the editor view in CSS (Don’t hit me up about incorrect terminology please!).
But with a bit of hacking I got this to work
Add to functions.php
add_action('admin_head', 'my_scroll_admin_fix');
function my_scroll_admin_fix() {
echo '<style>
#wpwrap .edit-post-visual-editor .editor-writing-flow {
max-width: calc( 1200px - 40px );
overflow: visible;
}
</style>';
}
I’m no AMP expert but if you haven’t already tried these tools they might lead you to discover why you’re getting the messages. I got one or two but they were structure errors.
But first of all, you’re getting lots of https errors and I see you’re using CloudFlare. Maybe try to remove the AMP pages from the CDN?
use #development=1 after the URL, open Chrome and then developer tools and put it in Mobile Emulation mode and check for AMP validation errors on the console.
Structured data tool
https://search.google.com/structured-data/testing-tool/u/0/
