9/10 Broadband issues are fixed by a reboot. Switching on and off definitely works, but why?
Shutting the power off on your router and turning it back is known as a reboot.
The router is the hardware, and within the hardware is software that is running the operation. Just like you may have to reboot your computer because it is running slow, the same also applies to a router. Occasionally, the hardware and software stop talking together correctly, and the reboot will re-sync them together so that they are operating correctly.
Turning off a router for a minimum of 60 seconds is usually recommended but sometimes, you may need to let your router power down for 20 mins to get the settings to fully resync.
Its complex stuff internet connectivity, and before you go spending any money on hired help to fix the problem, this is well worth a shot, even if 20 mins can feel like a long time its going to help in the long run.