I don't get email notifications anymore

I'm really disappointed with the gitter's notification system. I have the android app, but I never managed to make it send me any notification. That's beyond the point here, and I managed to survive for two years with only e-mail notifications, sent 1 hour after the message.

Now, a few weeks ago, gitter suddenly stopped sending me e-mail notifications, but the "all notifications" checkbox on the room's settings is still checked.

More info:

• I'm logging in with my GitHub account
• I'm using gitter on 3 different browser, but never at the same time.
• I have the app installed, but I'm never using it
• Several messages, on different channels were sent during the weekend, and I didn't get any notification.