Your MIFI works perfectly but sometimes the led that indicates 3G/4G turns off without any reason. (It can't be the signal because it is to the maximum in my phone)
So then I can't go back to conect myself to the MIFI and I have to turn off and turn on the MIFI again so that the led that indicates 3G/4G would turn on again.
Does the 3G/4G modem still works when the LEDs turn off?
If this happens, you can execute the following command without reboot. But I don’t know the reason. As LEDs never have such problem before. The LEDs only blink when there is data.