first, delete all your default apn in Settings > Wireless and networks > Mobile networks > Access Point Name
Delete all existing APNs and create a new one with by putting in the name "Digi Broadband" (can be any name, so i put "board"band..) and APN "3gdgnet". APN have to be exactly the same ( char in same case).
At the end, make sure the "Use data packet" is ticked and your APN is selected the green dot .
Done.