exchange administration center 2013 http 500 error

https://SERVER-FQDN/ecp?ExchClientVer=15

If you're installing on Windows Server 2012, please make sure that you've installed the Windows Identity Foundation Windows feature on all Exchange 2013 Preview servers. If it's not installed, install it and then reboot the server.

If you're installing on Windows Server 2008R2 SP1, install the Windows Identity Foundation package from here -http://support.microsoft.com/?kbid=974405.

Can you check the eventvwr and check for the errors there ?

2nd reset the IIS.

3rd. YOU can reboot the box and then give a try .

4th check for http://social.technet.microsoft.com/Forums/en-US/exchangeserverpreview/thread/54e5f450-2d3e-41af-b70b-27f6670a4b98/#b508ab57-2f57-4881-86aa-0f8e215e1232

http://social.technet.microsoft.com/Forums/en-US/exchangeserverpreview/thread/945fedae-8e47-4dd6-9d42-b82cd51a6901/