Newbie: y4mr and multiple vhosts aka serveralias

hi im using y4mr and gmaps_api_key.yml.

the file looks kinda like that:

stating:
ABQIAAAAzMUFFnT…

production:
foobar.com: ABQIAAAAzMUFFnT…
example.com: ABQIAAAAzMUFFnT…

now where im getting stuck is that i have both dns-entries pointed to
the webservers IP, but the rails app is always throwing me the errors
complaining abou the wrong key.
does anyone know how to fix that?
thx
tom