Im saying some phones will not pick up the APN and its usually the one off brands, like ZTE or older phones, sorry i didnt mean to say Zenphone was old lol, but i have had a few that didnt pull the settings but %95 of the time the phone pulls the APN...
Some phones will not pick up the APN (Most of the older phones). The new ones (iPhones, Samsungs, LG etc) will pick up the APN automaticlly. This is only a 1 off i have had to do this to a few older phones so far.