code: protected void handleAppendResponseError(MemberState member, AppendRequest request, AppendResponse response) {
      // If any other error occurred, increment the failure count for the member. Log the first three failures,
      // and thereafter log 1% of the failures. This keeps the log from filling up with annoying error messages
      // when attempting to send entries to down followers.
      int failures = member.incrementFailureCount();
      if (failures <= 3 || failures % 100 == 0) {
        logger.warn("{} - AppendRequest to {} failed: {}", context.getCluster().member().address(), member.getMember().serverAddress(), response.error() != null ? response.error() : "");
      }
    }
docs: Handles a {@link Response.Status#ERROR} response.