iphone not sycning with outlook calendar

I am having problems synching my Outlook 2010 calendar with my Iphone 6. My IOS is at 8.2 and ITunes at 12.1.1.4. My adds/edits to the Outlook calendar make it to my phone but adds/edits made to calendar on the phone do not make it to the calendar. This only started recently, within the last 2 to 3 weeks, with both the phone and ITunes getting updated to the latest version within that time. Phone is 64GB. Windows OS - Windows 7