Same Problem here!
In my case I discovered that image sources from HTTPS protocol didn't work after building the release (only works on debugging or using a browser)
My CSP: <meta http-equiv="Content-Security-Policy" content="img-src * data: https: ; media-src *">
<access origin="*" />
<allow-intent href="http://*/*" />
<allow-intent href="https://*/*" />
<allow-navigation href="http://*/*" />
<allow-navigation href="https://*/*" />
<allow-navigation href="data:*" />
I'm glad if you can help me!
If it works in debug but not in release and you are using https, that means the server certificate is not trusted or is not correctly installed.
While in debug, Cordova ignores server certificate errors and trust them even if they are not good.
Checking the url you provided in ssllabs, it says that there are Chain issues because of Incorrect order, not sure if that is causing the problem.
I could navigate to the url you provided with 2 Android devices, can you try to navigate directly to one of the images with your testing device and see if it loads?
Also, make sure your device is using latest System WebView (if you are in Android 5 or newer), some old versions had problems with some certificates.
And make sure the device date/time is correctly set, that can cause problems with certificates sometimes.