I have an MR6400 modem and I can't have an internet access trough it with my mobiles phones.
The MR6400 provide me an Internet acess with 4G.
If I connect a computer with the Wifi and the modem : I get Internet on my computer.
When I connect a mobile phone (Android, I don't have an iphone), the wifi connection is ok, but there is no internet access. I have a message which says "Internet may not be accessible" (it is a french translation).
If you encountered this problem in the past and fix it, I would be glad to here you about it !