MyBB Community Forums

Hello! First, excuse me if my english is a bit wrong, I am not english :/ 
Here's my forum : http://46.105.73.86/

So, my Mybb forum is working great, except the mail activation system. I have read that it isn't recommended to use gmail to send those mails, but my forum will not be very frequented and will not have to send thousands of emails daily, so I thought that it would be enough. I configured everything like a friend who used gmail too to send those mails; it is working perfectly for him, but for me, activation mails are not sent, and when I try to use the " lost password " function, I have an error message like this :


Here is also a screen of my email settings (sorry for the french panel ahah) :

What should I do to repair the problem? I searched some solutions in the forum but nothing worked; I am also ready to change my email if needed.

Thanks for reading, and thanks in advance.