Exchange 2010 Free busy not working from remote site to main site "exception message is: Could not find a base address"

Hi all , I have an exchange 2010 SP 2 environment with 2 sites , the remote site FL free busy has NEVER worked and I get this error on the remote site , is this related ?

thanks 

Log Name:      Application
Source:        System.ServiceModel 3.0.0.0
Date:         :
Event ID:      3
Task Category: WebHost
Level:         Error
Keywords:      Classic
User:          SYSTEM
Computer:      FL-CAS1.WOMBAT.LOCAL
free bust works from WITHIN the remote (FL ) site , but NEVER to the main (WASH) site , it has Never worked ,I am thing that this error is related

thanks I have no idea how to fix 



Description:
WebHost failed to process a request.
Sender Information: System.ServiceModel.ServiceHostingEnvironment+HostingManager/17256489
Exception: System.ServiceModel.ServiceActivationException: The service '/EWS/exchange.asmx' cannot be activated due to an exception during compilation.  The exception message is: Could not find a base address that matches scheme http for the endpoint with binding CustomBinding. Registered base address schemes are [https].. ---> System.InvalidOperationException: Could not find a base address that matches scheme http for the endpoint with binding
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