Lando services should be able to communicate with other services within their own app but also services from other apps. You can access a service within your app using the service name eg
database or a service in another app using the
<service>.<app>.internal convention eg
lando info for the hostnames you can use for each services.
You also can use your
*.lndo.site addresses to communicate between different services.
Cross app service communication requires all apps be on
If you want a service in App A to talk to a service in App B then you need to make sure you've started up both apps!