Yeah it happens a lot when the Devs do an update.. Just use your mouse, click on page that U can't scroll, then left mouse click and drag your pointer to bottom of page. This should scroll the page down for you. Hopefully they fix it, again, soon.
It's been happening to me for 2 days now on LCN and ZS On Firefox Right Click on a non-graphic part of the screen and select This Frame >>. Show this Frame Only. You can then use the arrow keys to scroll up and down. The scroll doesn't work on my Chrome
When this happens to me all i do is click on the page then use the tab key this will scroll down the page
