Often in cases like these there's something interfering with the line causing disconnections. It would be great if you could go through the steps below to help work out where the problem lies.
If you're connected via wireless please try connecting via Ethernet, and letting us know if you still experience disconnection issues?
If you're just getting connection drops on your WiFi, there's likely to be a problem with your modem / router setup. I'd recommend having a read of our WiFi guide here:
Please also make sure that there isn't anything else using your internet connection at the time you're testing. If for example there is a computer on your home network downloading updates, or uploading data to the cloud.
Also see the Why am I experiencing slow speeds on WiFi? page for more information.