Why can't you make a phone call and send a text message when the phone only has a 4G signal but no 2G signal?

Remove the check of "4G single data switch". When the "4G single data switch" is turned on, the terminal cannot use voice, SMS and MMS services. It is recommended not to open it. Path: Settings-Wireless and Network-More-"Enable 4G Single Data Switch". After the phone is turned off, you can make phone calls and send text messages. If it is unsuccessful, please contact 10000 or go to the local business hall to solve it. Customer service 48 answers for you. Guizhou users pay attention to WeChat payment, check the phone bill with one click, and the traffic, points, bills and detailed bills can be operated by themselves, which is convenient and fast.