Cannot receive incoming emails from outlook to my iPhone

I am still having issues syncing my outlook emails to my iPhone. My iphone keeps checking for mail but nothing happens. i can however send outgoing emails it just appears that the incoming emails are still a problem. Apparently this issue has been resolved but i am still encountering a problem. I get a message "Cannot get Mail. The connection to the server failed".Could anyone advise as to what the issue may be hand how I can resolve it?