What does not work? The lights do not go on or off. Or I do not see the gray lamp button. Or you can not open the Options page. These descriptions are better to understand your issue.
Try the basic steps here below that can solve this issue.
1. Restart the web browser
2. Remove your cookies and cache files
3. Disable the other browser extensions you have installed except Turn Off the Lights
4. Reinstall the Turn Off the Lights Browser extension
Also, make sure you use the latest version Turn Off the Lights browser extension in your web browser. You can easily test this, with uninstalling the extension and install it directly from the original add-on website (Chrome Web Store, Firefox extension, Opera extension, Microsoft Edge on the Microsoft Store, or on the official Turn Off the Lights website).