Default Not saving APNs??

Hi guys,

I'm currently on a different country and I want to setup the APN for internet access, however everytime I hit save after typing everything, it doesn't save it. And if I modify the one I have for my original carrier (T-Mobile) it also dissapears. What could be wrong? Thanks!

Nevermind I made it work, but anyway I found out that if I change the MCC and/or the MNC numbers it won't save the APN, I don't know why.
LG G2X (rooted, retired)
Samsung Galaxy S2 (Unlocked and rooted, retired)
Sony Xperia Tablet (Stock rom, awesome device)
Sony Xperia Z2