Hi @Adrián Gil,
Make sure that two kafka brokers are running.
1) Did you try restarting all the Kafka brokers from Ambari.
2) Do you see any alerts for Kafka brokers in the UI.
If you do not see any alerts in the UI, please check if the brokers are actually running by running
ps -ef | grep kafka
Also, pass the znode while creating the topic. ie, --zookeeper bigdata:2181/kafka
If this doesn't work, try running with replication factor as 1 just to confirm if it is the issue with create topics itself or the no of brokers.
Thanks,
Aditya