[Mail] No activation emails and No contact requests sent

[ShadowOne]

It's weeks that account activation emails aren't delivered and now I've just noticed that contact form doesn't work..

The thing is.. my own contact requests sent through the contact form are delivered to my email, while other members' ones not.

What's going on??
What should I tell to my hosting support?

EDIT: Looks like it was an issue with my hosting. I was told some hosters only allow emails with @yourboard to be used when sending automated messages.

[mmadhankumar]

check if this helps: http://docs.mybb.com/1.8/faq/mail/