I'm not sure. In my case i think it has more to do with the network signal. If 4g is weak but still not changed to 3g data does not work.
I will try to understand more about it. I don't use mobile data all that much but when i need it i want it to work.

I've read that changing preffered network to 3g should make it work. If i find a workaround this issue i'll post here.