I am just curious to know why this happens sometimes every couple of months?
The only way to correct this issue is to unplug the modem and wait 30 sec and then plug it back in.
It's a real PITA, I wished Hughs would fix this from happening periodically at random times.
Usually this is a symptom of an erratic wifi connection that has corrupted the DNS, not a problem with HughesNet or the modem. You can solve most of the problem by moving your device closer to the modem or by using a LAN cable.
Is it the only device connected? Once the DNS is corrupted by any one device, it affects all of the devices connected to it.
There is some additional info on the following website that may help...
To add on to the great info being shared already, this explains it for a regular internet user, as opposed to a website owner: https://us.norton.com/internetsecurity-how-to-your-connection-is-not-private.html#notprivate
But, that's precisely the procedure for clearing the modem's DNS cache.
It's possible that instead of poor wifi there's a site or some application that's hitting the DNS too fast, and not waiting for it to respond in time before going on to something else. That will confuse it but is kind of a rare situation. I used to see it a lot with the 1100, but not with the 2000-series modem.