If suffering from intermittent disconnections or NAT-like issues try disabling IP flood detection and/or firewall protection.
If you have issues connecting wireless you may want to disable a setting called XPress™ Technology. To do this click Wireless up top-> Click Advanced on the left-> Change the dropdown for XPress™ Technology to Disabled.
While this gateway is dual band, it is not able to run simultaneous 2.4 GHz and 5 GHz signals. Your choices are either to lock it to 2.4 GHz or to set it to Auto, which causes it to switch back and forth between 2.4 GHz and 5 GHz. Make sure to select 2.4 GHz.
If the firewall is set to maximum or medium security this device will give out an MTU Error.