Install ubuntu Image on docker via script

On my synology I have docker Manager
Via the following Script I am able to get Firefox installed and running

docker run -d --name=firefox
-p 5812:3000
-v /volume1/docker/firefox:/config
-e PUID=1026
-e PGID=100
-e TZ=Europe/Berlin
-e PASSWORD=pass

But now I am looking to install ubuntu as docker…
I searched sloot but seems the access is not given.
This Script above is working, but I replace the last line with

Example of Error I get

Unable to find image ‘6901:6901-v’ locally
docker: Error response from daemon: pull access denied for 6901, repository does not exist or may require ‘docker login’: denied: requested access to the resource is denied.
See 'docker run --help

Can you pls Help me to get Ubuntu running as docker Container?


Please, format your post according to the following guide: How to format your forum posts
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But you must have changed something else too, since the port in the error message is not in the first command. Check your parameters. The error message is pretty clear about that the port mapping was interpreted as image name.