Issue with Images delivered over CDN

I have a Smush Pro license and use lazy loading as well as the CDN. For the CDN I have every feature activated. The issue I see know is that my images are not loaded reliably. By images I mean PNG and JPG.

I have done a cross browser test and you see the results here: https://app.crossbrowsertesting.com/public/i3917a5a8febdcd1/screenshots/z0aafe24c0253fff66bd

Basically Windows does not work in any browser and Mac just works in Chrome but not in Safari. Android does not work and iOS does.

I looked into it in more detail and the Chrome Browser console on a Windows machine said: Failed to load resource: ERR_NAME_NOT_RESOLVED

Of course I deactivated the CDN feature then to get an understanding if this is actually causing the problem. I also checked with just CDN activated but all the additional options (WebP, background images) off. I can confirm that activating the CDN is the source of the problem, because you can see that the page looks fine with CDN deactivated here: https://app.crossbrowsertesting.com/public/i3917a5a8febdcd1/screenshots/z04ca691b808737b3067

Any help would be highly appreciated because we use Smush on multiple websites now with this configuration so we have quite a problem here.

The page I need help with: [log in to see the link]