4.1 jelly bean - APN doesn't save in Tablet AOC Breeze

I have a tablet AOC Breeze model MW0712 with Android 4.1.1.

When I want to save an APN I do: Settings -> Mobile networks -> Access Point Names -> New APN

But after editing the APN settings, there are no button to save the changes.

The only proven way I have to save an APN is typing in the fields:

• Name


• APN


• Username


• Password

and leaving blank the MCC, MNC, Authentification Type and APN Type fields. With this way the APN is saved but doesn't work. If I edit the APN I've saved and I put the values for these fields, the APN disappears.

With Root Explorer I open the apns-conf.xml file (readonly) and I see full of different APNs, but APN selection screen (Settings -> Mobile networks -> Access Point Names) is empty.

I haven't rooted the tablet.