Okay, I think I found the answer here:
https://docs.mendix.com/developerportal/deploy/deployment-location/..
I need to use sub domains:
“If you want to deploy several apps on the same domain, you should use different subdomains to identify the app. For example, use https://appA.apps.mydomain.com/
and not https://mydomain.com/apps/appA
.”