You may have to completely exit and restart your browser for the blocks to start working, or for the blocks to go away once the blocking time is up.
The screenshot below is an example. You'd have to close both the browser windows to get the browser to exit. If there is more than one window open, hitting Alt-F4 only closes the current window.
Here's another example. You don't see any browser windows, but the Chrome browser is still running, as you can see from the shaded box that Windows has put around the Chrome icon in the taskbar, in the lower left of the screen. To exit the browser, you need to click on that icon and close all the Chrome windows that come up. Other browsers work the same way.
Still having problems?
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