Check your computer’s sound levels, to make sure your volume is not muted or at a low level. On PC, use the "Sound" icon in the bottom-right of the screen. On Mac, try the volume option in the Menu bar (top right of the Finder)
Is your email address already registered with Concert Window? Try logging in first and then buying the ticket. If you’ve forgotten your password, you can reset it. If that still doesn't work, try using Chrome, Safari, or Firefox on a computer or laptop.