My sign-up code doesn’t work

Reviewed October 2026 1 minute read

If the app says Double check the sign-up code or contact the organizer for help, or shows “invalid” or “rate limit exceeded”:

Enter the code with the same capital letters and hyphens, and no spaces. Copy and paste works best. Don’t add extra words or a year.
Codes from earlier challenges may no longer work. Check the latest invitation.
After many tries in a short time, more tries are blocked for about an hour, and even the right code shows as invalid. Wait, then try once.
On office Wi-Fi, try mobile data. Many people signing up from one network can trigger the block.
Update the app to the latest version.

Still not working? Ask your organiser to check the code, or contact support with a screenshot of the error.

Applies to