来自Firefox的AspNet5 beta8预检请求不返回找到的元素位置：moz-nullprincipal

I have an AspNet5 beta8 website mydomain.com:80 and api running on mydomain.com:81. Only the port is different. I did configure Cors and it does work very well in IE11 and Chrome. Unfortunately I cannot make it work in Firefox version 42.I have an AspNet5 beta8 website mydomain.com:80