Starting instances in a domain other than root fails,

[alsko-icom]

• In Cloudstack v4.20 I created a new domain and a subdomain under it.
• Then I created a domain admin user for the domain and again a domain admin for the subdomain. Same username and password.
• I logged in to the subdomain to create an instance there.
• The instance during creation does not have the option to configure which cluster/pod/host it will use, cool so far (I would dedicate something while in ROOT if I wanted).
• After creation, I cannot start it with error "no suitable host found for VM". So I log off and log on to root.
• When I try to start the instance while in root domain, I am asked to which pod/cluster/host to start it on and whether to remember last host.
• After selecting whatever options, the VM starts normally.
• Why? I am obviously forgetting something but could not read enough through it. Some configuration I am missing? In ROOT (or subdomain) can I somehow choose pod/cluster/host once so i don't get a selection prompt every time i want to start it?
• I have checked that zone, pod, cluster and hosts are not dedicated somewhere.
• I also changed Global Settings Vm allocation algorithm (vm.allocation.algorithm) from random to FirstFit.
• Accounts are not nearing quota.

Thanks for any help!