UI access via Systemname Volumio

I have a Raspberry PI 3 B running with system name Volumio and I can access via UI / browser with address volumio.local (Win10 PC’s, Android phones).
Now I have build a second Raspberry PI 3 B and therefore changed the name of this to Volumi2.
It is still possible to access the first with address volumio.local, but never possible to access the 2nd one with address volumi2.local but only via its TCP/IP address.
Now I put the second RPI in a different network and changed name back to Volumio and it works with address volumio.local, but not on all devices (Android phone not, Win10 latop yes).
Both RPI’s have newest volumio software (2.201) installed.