Which Voice Control are you using? Which station are you attempting to select? There should be something unique about your station. For example asking for “NPR” or “Public Radio” would not be unique, but the station’s call letters will be unique.

I use Sonos Voice control.

Is it Czech radio: “Radio1”

I have attached a printscreen.

Likely Czech Radio 1. I wasn’t able to find anything unique about this station, with respect to voice control.

I found one solution.

When was the last time "Radio 1" played. So just say "Hey Sonos, play radio".

Then it works.

Too bad the radios can't be renamed.

Thank you for cooperation.

Use the Sonos app to make a Favorite from a station and give it a unique name, then your voice service should see that.