Mup setup problem

When I run mup setup I get an error message about a refused connection I get an error saying
Error: couldn’t connect to server, connection attempt failed: SocketException: Error connecting to :: caused by :: Connection refused :

mup status says
App available through reverse proxy
- Available in app’s docker container: false

I am using mup 1.5.7 and meteor 1.10.2. mup.js says
docker: {
image: ‘zodern/meteor:root’,
env: {

MONGO_URL: ‘mongodb://mongodb/meteor’,
mongo: {
version: ‘4.4.12’,
port: 27017,
servers: {
one: {}
Any hint where to search for the problem?

can you ssh to that server?

That’s the mongo database - probably mongo isn’t running on the target server. It’s best practice (and also easier) to have your database hosted on an external server

I have another Meteor App (using different ports) running on the same server. The new app is to be installed on a subdomain of the same domain.
The background info is, that I migrated the server from Ubuntu 16 to an Ubuntu 20 server. The migration of one app on the main domain using the Plesk migration tool was smooth but the app on the subdomain was not correctly migrated and I try to re-install it now.
For both systems frontend server and backend server run in different containers on the same server.