>Cannot delete subscription lists, even when they no longer contain subscribers.
Mhh, this is odd, could you please share the name of the list that you are trying to delete? I am asking because the WordPress and WooCommerce users’ lists can’t be deleted as explained here.
The lists I am trying to delete are the ones I have created, e.g.: “Politique” or “Profession écrivain”. It annoys me to see these useless lists lying around in the list table. Strangely, it was possible to delete one of these lists that I had created, but not the others (4 in all). Even the WordPress user list can be put in the trash (not permanently deleted), but not the other lists.
I tried deleting a list again and indeed saw the message saying that the list could not be deleted because it was in use by an email. Yet the list was not selected in the mentioned email and additionally the email was disabled. Looking further, I found that old versions of this email, in the trash, contained the selection of lists to be deleted. By permanently eliminating these older versions, I was able to remove the now unnecessary lists.