Nothing changed in your code. All of a sudden, a tidal wave of errors start happening for Microsoft Edge users. What the heck happened? On August 28th, 2019, many TrackJS customers saw a sudden surge in errors from Microsoft Edge browsers: Failed to construct 'Request': Invalid Argument and Failed to execute 'fetch()' on 'Window': Invalid argument". Our Debugging blog series explores symptoms, causes, and solutions to common JavaScript errors.