If you’re running docker, you must expose the Port you type in in the configuration accordingly in the container. Either use “host” as network mode or simply add “5678:5678” in the ports part of your docker-compose.xml.
If you’re using the german alexa-enpdoint, then you don’t have to change anything on the card - except “This IP” and an correct/empty “File Path”.
If you’re using any other country/language settings, please check in the docs of the Node-Red node: bbindreiter/node-red-contrib-alexa-remote2-applestrudel: Node-Red Nodes for interacting with Alexa