CONNECT to remote clusters

Hi fellows,
I need your help so bad. I am running 2 elasticsearch cluster as docker container http port 9200 transport port 9300

But when I try to configure the remote cluster like that: name docker-cluster seed nodes: ip-address:9300 I get not connected Ensure that the seed nodes are configured with the tansport not the http port . As far I understood 9300 is the transportation 9200 the http port. So what did I configure wrong and how can I fix that. Many thanks in advance Uli