by Frédéric Massart.
Hi Mario,
I have tested using Android 4.1, 5.0, Google Chrome and Google Chromium (insecure) and I could always connect and use the site without any problem.
One thing I noticed, which might be a source of problems in some scenarios, is that the domain using HTTPS is reachable, but has an expired certificate. But also, that HTTPS site is not Moodle.
Maybe you should investigate there and remove the SSL version of your site, so that the mobile app does not get confused.
Lastly, applying the patch we introduced here might help: MDL-50107
Let me know how you go.
Cheers!
Fred