After update of Sendy to Version 184.108.40.206, the integration with Joomla is not adding users to the list anymore. I think the reason for this is added API key (beside the list ID) and perhaps it must be included in the API call. Could you please update your plugin to allow adding the API key in the settings?
I want to thank you for this useful integration with the best PHP script for mailing lists.
As of 220.127.116.11, the API Key is now required.
I've modified the integration to add it as a parameter in the module and put it into the API call.
Module's XML gets this, and then it's used in the prep for the actual call:
<field name="api_key" type="text" label="API Key" description="The Sendy API Key (required for API calls as of 18.104.22.168)" default="" />
I'd be happy to post up that code if asked, but I suspect SourceCoast can add it as well. It took me about 20 minutes. If so, I can do it in a week (I'm about to leave for Amazon AWS:ReInvent in Vegas, so I can package it up and post when I get back). But again, it's a very trivial change, so I suspect SC will do it before I get back