It seams that to use spotify with alexa I have to link my account to alexa.
It really, for me, not clear how to do this.
I goes to my alexa account, settings-> music & Media and I can't add any service. When I select "Chose default music service", I can see Spotify, but I'm not able to select them.
Best answer by stek
amazon -> your account --> digital content --> manage content and devices-->Settings ->then youll see settings and you need to change the country to UK
Then I user http://layla.amazon.co.uk instead of alexa.amazon.co.uk
Now it works file