I got 404 when Sitecore tries to use it's own web-api.
the url is
/-/item/v1?sc_itemid=%7B11111111-1111-1111-1111-111111111111%7D&scope=c&sc_database=master
when I check the logs i got the following info
INFO [Item Web API] An attempted to execute remote call was declided, because current mode is 'off'.
does any one know how can I turn it on? all of itemwebapi.mode values in config is set to StandardSecurity
It started to happen when we upgraded our Sitecore website from 6.5 to 7.1. I installed the fresh Sitecore 7.1 and it doesn't have this problem.
we found the Answer of our problem after comparing the configs of freshly installed sitecore with our upgraded site. in Sitecore.ItemWebApi.Config there is a patch to add sitecore.ItemWebApi after Sitecore.Pipelines.HttpRequest.SiteResolver and we have our custom dll so it couldn't find it!