My Outlook 2011, deletes mails on the mailserver as soon as it detect the mail in inbox(not read). The email setup is IMAP,and i have 3 mails accounts, whits is setup similarly, it only gives problems on one of them. 

I use one.com mailserver. One's hotline can not help, they say it is a Outlook problem.

It is a big problem when my mac detect the mail before my Iphone, then it is not available on the Iphone.  

It works perfectly in the email program Thunderbird.....

Help don´t know what to do?