[exim] Aliased address rejected for non-local deliveries

Hello,

I have a new problem. In /etc/aliases there are records

user1alais: user1
userlist: user1,user2,user3

user1, user2, user3 are local accounts.

Mail sent to user1alias@??? is accepted.

Mail sent to userlist@??? results in '550 User unknown -
userlist@???'

May I ask how that can be solved?

Thanks.