Is it possible to delete subscribers in MailPoet?
Yes, it is possible to delete your subscribers from your MailPoet lists.
If you want to delete subscribers from the Trash but you can’t, this means they are either WordPress Users or WooCommerce Customers.
As these users are automatically synced between MailPoet and your website, to delete them you have to delete them first as “Users” or as “Customers” in the WordPress dashboard.
WordPress Users should be deleted as a User by going to the?WordPress dashboard > Users page: https://kb.mailpoet.com/article/133-the-wordpress-users-list
Customers added to the WooCommerce Customers list can not be removed from this list or from the MailPoet plugin, unless you delete their order from the WooCommerce plugin. They can be marked as “Unsubscribed” though: https://kb.mailpoet.com/article/278-the-woocommerce-customers-list
Reference: https://kb.mailpoet.com/article/304-why-i-cant-delete-my-subscribers