Wcf error: There was no endpoint listening

Please help me 

 

Error msg: There was no endpoint listening at http://URL that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details.

 

My WCF is called in Windows service.  While my service hosted in 32 bit functions properly after migration to 64 bit.. It respond to some calls and throws the above error.

 

Why it respond to some calls and not the other. What should I change to fix it.

 

Thanks a lot in advance.