HTTPS status 0 in the release build

[tomkuipers]

I have encountered the same once. Are you running an Android app? See my comment here:

From http to https -- preparing the app

Beware that on Android handling of ssl connections is different for debug and release versions of your apk. I learned this the hard way. Self-signed certificates work in debug mode but not in release mode. Test if your setup will work in release mode by setting ‘android:debuggable=“false”’ in your manifest file. Also run an ssl validation check such as https://www.digicert.com/help/ to check for certificate chain issues. These will also fail in release mode but work in debug mode. I used the d…

In short, android release builds are more strict regarding ssl issues compared to debug builds. Check your certificate.