@Mapanima
Hi, when the problem happens, the M7650 shuts down completely or it stays on but no WiFi signal?
You mentioned that you need to activate it by hand, do you mean long press power button or short press?
Usually the MiFi device only turns off automatically when there is no power or the device is overheating, so if it shuts down completely when there is still enough power, please check if it is overheating; and if you mean WiFi issue only, please note that Power saving mode is enabled by default, and if no client device connected to it for 10 minutes, it will disable the WiFi automatically, if necessary, you could also disable the power saving mode or adjust the WiFi Auto-disable time.