No page access permission for non-admin roles


I have created new user and assign her the Editor role. When I try to login to the WP backend as this new user, I get the the following message:

WordPress > Error

You don’t have permission to access this page.

When I login with my Admin password, everything is ok. Also, when I promote the new user, from Editor to Admin, everything works fine. The problem remains when the logging in with non-admin roles.