I contacted my hosting.
they told me that their side all (mail server) is well.
i sked them why i can send to my mail@mysite.com and not to others_email@Gmail.com or Yahoo ....
they told me this : It appears my emails have been reported by multiple providers (such as Yahoo or Comcast) as containing spam, this in turn has flagged in they outbound email filter.
And they had removed my domain from this filter 2 days after !!
finaly after 7 days ( of questions answers ) they told me this :
" There were recent changes to SPAM filters by Gmail, Yahoo, Msn/Outlook, and others that have been causing similar problems.I would suggest talking with the developer of the plugin that sends the email to find out how the link is generated, if it is a shortened URL at all, then the emails won't make it through "