Denish on "[Plugin: Newsletter] showing access denied for custom user role"

Hi,

I have custom user-role created which have rights for managing posts, But when he is trying to create new newsletter - It's showing "Access Denied" and Login first.

Please find attached screen shot in below url

Can you tell me which are access required to custom user role - to create newsletter??

Screenshot: https://www.diigo.com/item/image/5oerc/a0iu

https://wordpress.org/plugins/newsletter/

on main setting I have already enabled editor to access the plugin. still it's not working

<iframe src="<?php echo wp_nonce_url(plugins_url('newsletter') . '/emails/preview.php?' . time(), 'view'); ?>" height="700" style="width: 100%; border: 1px solid #ccc"></iframe>

I think above code is ristricting user having custom capabilities restriction user to view priview.

Custom user already having manage_options capabilities.