First of all, what is network? It is a complicated system of roads, lines, tubes, nerves e.t.c that cross each other and are connected to each other. Before you can be able to restore network to your phone or device, you have to know the cause of network failure.
There are four causes of network failure I'll share with you.
They are:
Network failure caused by environment: this network failure cannot be solved except one leave or displace from that environment where network is out of reach. The solution to this is to change your location to a preferred network area or change your network provider.
Network caused by phone: some phones are the cause of network failure itself because its either disrupted by virus or unable to function properly on its own. The solution to this is for the device to be changed.
Network failure caused by simcard line: this is another problem that facilitates network, some network providers have poor network coverage and this affects the users, when suffering from such poor performance. The best solution is to change your network provider to a more better platform.
network failure cause by system: this is not quite a problem but it makes users anxious, whenever you notice network problem, after switching off your device, the same problem persists. Be patient. The network failure is definitely from the server.
I hope you find this helpful.