Misombre

Got an email at 23 h 30 from a customer : Your website is broken, I can't sign in with the token you gave me...

I have faith in humanity, so I double check the system. Everything's okay.

The customer then send me a screenshot of the form filled, and tell me that he've been very careful to type himself the token (instead of copy/paste)...

Result : he had actually inverted two letters in the token...