iphoto won't update

I just updated to the mac os sierra and upon opening my computer again found that the iPhoto app wasn't working and was directed to the app store to install an update. When I press update a message comes up that says "this update is not available for this Apple ID either because it was bought by a different user or the item was refunded or cancelled" but then a second message comes up that says " there was an error in the App Store. Please try again later. (,)" I have been able to update a different app since then so I don't understand what the problem is? Surely iPhoto came with the computer when I bought it?