User interface does not finish to load

[Alluka]

Check Point 600 Appliance Version:R77.20.80

When I want to enter the Next Generation Firewall,
The user interface does not finish loading, this is happening to me very often.

The icons are not shown, the checkboxes are not visible if they are selected or not.

I have tried all browsers, Google Chrome, Mozilla FireFox, Internet Explorer 7,8,9,10 ..., Microsoft Edge and the problem persists

Any ideas why this happens?

[PhoneBoy]

It suggests there's some sort of underlying network issue, or that the appliance is operating under CPU load.
Have you gone into expert mode to do any troubleshooting?