I am trying to add new role with custom capability here is what I have done so far :

add_role('event_manager',__( 'Event Manager'),array(
        'read'         => true,
        'create_posts' => true,
        'my_custom_cap'   => true,

    ));

the new role have been added successfully and its working but when I am logged in with that custom role I can only see admin bar without having access to wp-admin.
based on the custom role I am adding new admin menu inside wp-admin with this code

add_action('init','my_custom_event');
function my_custom_event(){
   if (current_user_can( 'my_custom_cap' )){ // admin actions
       add_action('admin_menu', 'my_custom_plugin_menu');
   }
}

my issue:

• I don’t have access to the wp-admin to use my new admin menu