Back button stopped working

CD back button has suddenly stopped working. Right click and select back clears page and reloads the page I tried to go back from.
Select back button in top bar and the same thing happens.
If I hold down the mouse on the back button then I gate a list of sites I have visited and can go to them by selecting them from the list.

Hi scbs29,
In case of some form of corruption has occurred in the cache/history, try clearing your browsing data and try again.

Kind regards.