I got a call now. And, I succeeded in fixing the situation where a call can't be got.
Booted the mobile phone in the situation in which WIFI connection is turn on. Then, can get a call on WIFI or 3G network.
Booted the mobile phone in the situation in which WIFI connection is turn off (3G is ON in this case.).
In this case, can't get a call on 3G network. Then, even if after turn on WIFI, can't get a call.
Is this #2 behavior based on this server's spec?
I need use only 3G. So, please teach me about #2.