private void onFailedResponse(final long currentTimeMs, final Throwable exception) {
        coordinatorRequestState.onFailedAttempt(currentTimeMs);
        markCoordinatorUnknown("FindCoordinator failed with exception", currentTimeMs);

        if (exception instanceof RetriableException) {
            log.debug("FindCoordinator request failed due to retriable exception", exception);
            return;
        }

        if (exception == Errors.GROUP_AUTHORIZATION_FAILED.exception()) {
            log.debug("FindCoordinator request failed due to authorization error {}", exception.getMessage());
            KafkaException groupAuthorizationException = GroupAuthorizationException.forGroupId(this.groupId);
            backgroundEventHandler.add(new ErrorEvent(groupAuthorizationException));
            return;
        }

        log.warn("FindCoordinator request failed due to fatal exception", exception);
        backgroundEventHandler.add(new ErrorEvent(exception));
    }
Mark the current coordinator null.

@param cause         why the coordinator is marked unknown.
@param currentTimeMs the current time in ms.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/CoordinatorRequestManager.java