Open Stack

Dear OpenStack Dev Team

May I ask you some questions about the Openstakc Mitaka Horizon Dashboard?
I have followed the Openstack online installation document and your installation guide http://docs.openstack.org/mitaka/install-guide-ubuntu/
But after I installed the horizon, I cannot access the Horizon.  
It showed this following error.  I am not sure what was wrong. but I have followed the same steps, and installed the openstack Mitaka twice, but I still got the same problem again.
I user two physical servers, 1 controller and 1 compute node. All are Ubuntu 14.04
I am not sure what was wrong, I followed the same steps on the documents. I think should be the apache configuration problem.
Could you please give me a hand on this? 
==================Internal Server ErrorThe server encountered an internal error or misconfiguration and was unable to complete your request.Please contact the server administrator at webmaster at localhost to inform them of the time this error occurred, and the actions you performed just before this error.More information about this error may be available in the server error log.Apache/2.4.7 (Ubuntu) Server at 10.145.213.30 Port 80
Thanks a lotWally

 		 	   		  
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