Email Problem

Hello all

I recently installed WordPress 3.9.1 on my hosting (web.com), I changed the theme and everything is going well.
But when I tried to use the registration form in order to test, I noticed that the email containing the password did not arrive on my inbox (in my dashboard, I find the new member), also I tried it with contact form 7 and other plugins but same problem.

Please can anyone help?

Thank you