Cannot apply to Winamax challenge

I’ve finished the Winamax challenge and tried to apply to the job offer, but I got an error (I think it was error code -1).
A message box said to contact an email address but the message vanished too quickly so I could not copy it (hence why I am posting here).
Is there an issue with this feature?
Thanks to fix it.

Sorry for the inconvenience, we will investigate. We have the error message in our logs.