How does AMPS report the specific failure in replication validation?

When replication validation fails, an instance will log the reason for the validation failure with error 1E-0065. That error will contain a short description of the reason for the failure.

For example, if the remote side replicates topics that are not recorded in the transaction log for this instance, the error might look like:

2020-05-04T15:35:19.3599350-04:00 [95]
error: 1E-0065 Replication validation rule [txlog] from source [other-AMPS]
could not be satisfied. Reason: topic [ImportantStuff] of message type [json]
is not configured in this instance's transaction log.

In this case, to satisfy the validation rule, you would add ImportantStuff to the transaction log for this instance.