Redirect after login based on user role (custom login page)

Try this. It works for me.

add_filter( 'login_redirect', 'redirect_non_admin_to_dashboard'), 10, 3 );
function redirect_non_admin_to_dashboard($redirect_to, $requested_redirect_to, $user ) {
    global $user;
    if( ! isset( $user->ID ) ) {
        return $redirect_to;
    }

    if ( ! in_array( 'author', (array) $user->roles ) ) {
        $redirect_to  =  site_url().'/dashboard-teacher';
    }elseif( in_array( 'subscriber',(array) $user->roles ) ){
            $redirect_to = site_url().'/dashboardwwp-student';

        }else{
            $redirect_to = site_url();

        }
    return wp_validate_redirect( $redirect_to, home_url() ); // return a safe redirect url between the site.
}