Android: SSLHandshakeException when connecting to my https server

The https connection to my API hosted on my gandi.net https server SUDDENLY no longer works (the problem probably started on April 1st 2024). This problem only occurs when the connection is made from an Android device (several Android devices tested); no problem when connecting from iOS.

Here is the error that is obtained on the client side (i.e. in the Android app) when a connection attempt is made:

NoConnectionError: javax.net.ssl.SSLHandshakeException: Chain validation failedjava.security.cert.CertPathValidatorException: Response is unreliable: its validity interval is out-of-date

Everything worked properly before. The problem appeared suddenly on ALL MY APPS in production.

I tested several Android devices, in wifi and 4G, two have identical DNS in the phone settings, the others have different DNS. I also tested the API by launching my Android app in an Android simulator on my Mac OS computer, same problem.

As already said, the API works without problems on iOS.

When I open the API root link in a browser, whether in a browser on my Mac or on my various Android devices, the API responds correctly.

The problem therefore only occurs when the API is called from the Java code of my Android app. The problem appeared suddenly without me being able to explain it.

I suspected a problem with the time change this weekend (1 hour change). But my devices are on time (correct time and date set automatically), I restarted my devices, cleared the app cache, the problem was not resolved.

I restarted my https instance; the problem has not been resolved.

Any idea how to solve this issue ? What should I set in my network_security_config.xml ?

Thanks for your help.