Hi

This does not sound like an issue with Firefox, but have you checked your email service providers spam or junk mail folder?

Yes, thanks... I have checked. The problem is with Kijiji, when I want to change my password... I don't get a confirmation email. I also tried to register for a game developer site, and the confirmation didn't come there either. Any suggestions? Thanks in advance.

Confirm your personal information on that website. If nothing helps, contact its support.