Hi lenaf21917833,While sending API Calls to Campaign Server, in case of
unavailability of the Server, you would receive corresponding error
messages.In that case, you will have to resend API Calls.If for some
reason, the API message was received within Server but didn't turn out
to be successful, then the Campaign (Real-Time) Server would continue to
target end-user until the specified threshold of retries is achieved.