Clients SBS 2003 server was syncing with phones fine.
Client got new software that allows access via IIS. (May or may not have bearing)
Had ISP change forward port 80 to server for the IIS access. (ISP manages Cisco firewall for client)(May or may not have bearing)
There was an issue with one of the pages for the new software, client dealt with company directly to resolve that issue.
Client calls several days later to say no smartphones are receiving email.
I have gone through all the settings in IIS (REF:AlanHardisty)
I have removed all the VD's from IIS and recreated. (twice)
I have attempted to remove IIS and Form Based
I still receive the HTTP 500 response error on testexchangeconnectivity.com
Any help would be greatly appreciated!!!