Hello Govind,
Can I suggest you to check below settings.
1) Communication Scenario view under the Application and user management.
Here you should find the Communication Scenario : Manage Exchange Rates
2) Check in communication Arrangements under the Application and user management.
Here you should be able to see the communication arrangement : Manage Exchange Rates and would be able to edit and check the settings there.
Alternatively, you can click on "Link" under the Documentation field to get more details on the service.
If that helps. 
Cheers,
Harshal