Deployed asp.net core web site 404's on some pages which work locally

I have deployed to a IIS server and if I try to browse to a page that requires authorization then it redirects to the login page which is fine. However on POSTing the login page after filling in username and password it just 404's, even though that works fine locally.

Trying to browse to another page all together which doesnt require you to be logged in gives a 404, although it works fine when running in Visual Studio, its really stange.

In previous asp.net 4x applications I have done I had to add  <modules runAllManagedModulesForAllRequests="true">   to the web.config to get urls to work properly, if I try doing that on this asp net core app though I get a 500 error.