Hi @mgray,

The error looks like it’s due to the first three field settings that aren’t correct:

  1. Data center looks incorrect. If you look at the front of the URL in your Mailchimp account, looks like your data center is us19. Swap that out for the placeholder that is currently “us01”

  2. list_id is not your api key. You need to go to your Mailchimp list settings to get the list id (it’ll be in a red font color)

  3. You still need to fill in the subscriber email address as MD5 hash in that 3rd field in the action settings. See this:

Also, just in case - check that your API key is correct in the plugin settings (not the action settings in the workflow). The key you happened to enter in the action settings looks really short, so just want to make sure you have the right key in the plugin settings. This will help you find the right key: About API Keys | Mailchimp

You can find more instructions here on the plugin too: Mailchimp Extended Plugin | Bubble

Update all of those first and give it another try.