Fix email in plesk magento and wordpress

When placing an order in magento customer doesn,t get sales email when using gmail, other emails are working In wordpress when customer writes posts he doesnt get any email notification to his email (to any email, gmail, hotmail, , ) (plug in installed) To do a test I copied the sites content and replicated it on a different domain in WHM and everything works fine. So my conclusion is that magento or wordpress are not the problems, the Plesk server is the problem. It must be something with server configuration. Notes I can send emails to gmail accounts fine. Parallels Plesk Panel v10.4.4_build1013111102.18 os_CentOS 6 Hosting 1and1