Hi Chun,
I’d state that the exception which is thrown by your Command Handler which makes the SOAP call should be made “non retryable”.
The simplest approach to reach this would be to catch the exception, which is currently ending in the RetryScheduler, in said Command Handling function and rethrow it as an exception which will not be retried.
By the way, I assume this Command Handler your referring to is not in an Aggregate, but rather an External Command Handler, right?
Hope this helps you out Chun!
Cheers,
Steven