title: E-mail sent through PHP Mail() not received by Microsoft Outlook 365 Only
body: <p>We have a web application which is using the php mail() function to send emails. Emails are received perfectly by all popular mail clients like gmail, yahoo, etc. but only outlook 365 not receiving any emails not even in Junk folder. </p>
  
  <p>Amazon EC2, Ubuntu 14.04, Plesk 12, LAMP (Apache, MySQL and PHP) </p>
  
  <p>We have checked email logs also but its not showing any errors. It looks like its sending email but its not received by Outlook 365 or they are blocking or something.</p>
  
  <p>We have tried changing "\r\n" to "\n" but its also not working.</p>
  
  <p>We have tried by changing SPF records but its also not working.  <a href="http://365.webbrewers.com/blog/Lists/Posts/Post.aspx?ID=44" rel="nofollow">http://365.webbrewers.com/blog/Lists/Posts/Post.aspx?ID=44</a> </p>
  
  <p>We have been trying to find out a solution everywhere including Microsoft Community, Plesk (Odin) Community, PHP Community, Ubuntu Community, Amazon EC2 Community and didn't find the work around.</p>