ActiveSync on Exchange 2010

Have exchange 2010 running and email is working along with owa. active sync gives an error on test as below:
Attempting FolderSync command on ActiveSync session
  FolderSync command test failed
   Tell me more about this issue and how to resolve it
   Additional Details
  Exchange ActiveSync returned an HTTP 500 response.  
 I have looked through the exchange to resolve but no luck.  I do not know if I have a setup issue on my server.  The server has a local name of Exchange-Server the External URL is mail.petrilloarchitecs.com.  Tried with SSL turned on and off no luck. right now when the iphone tries to pull mail it gives no error just goes through and states connecting and the updates with current date and time but no mail.  tried change login server on iphone to mail.petrilloarchitects.com/exchange that gives me a failure error on the phone as well unable to connect to server.I am not sure I am in correct area at times when I am changing settings on the 2010 server as per some of the sugestions and i do not want to impair a working production server as this point.  we have transitioned from a 2003 exchange sp2 server to the 2010 exchange server recently and the activesync worked on that previous.  I have one(1) iphone that needs active sync at this time, others are on blackberry and we are forwarding mail for now to them.  The 2003 exchange server is still up unitl I can do a final cleanup on the server from the move of mailboxes it will be going away soon (this weekend hopefull).  any help?