The cookieHandler setting for identity may appear to sabotage your application!

I had this at the base of Web.config (well, Web.template.config which builds out Web.config).

   <system.identityModel.services>
      <federationConfiguration>
         <cookieHandler requireSsl="false" />
      </federationConfiguration>
   </system.identityModel.services>
</configuration>

 
 

I changed it like so and my application would not load whatsoever!

   <system.identityModel.services>
      <federationConfiguration>
         <cookieHandler requireSsl="false" path="/" />
      </federationConfiguration>
   </system.identityModel.services>
</configuration>

 
 

A coworker suggested that I just needed to clear cookies, but honestly, when removed the path setting, reran the app (got positive result), and then readded the path setting (got positive result again), that also fixed things too.