Make sure you use the latest version of this browser extension. You can easy test this, with just uninstall the extension and install it direct from the original add-on website (Chrome Web Store, Firefox extension, Opera extension, Microsoft Edge on the Windows Store or on Turn Off the Lights website).
Try this basic steps.
1. Restart the browser
2. Remove you cookies and cache files
3. Disable the other browser extensions you have installed
4. Reinstall the Turn Off the Lights Browser extension