Unable to Locate Public API Key

I’m having trouble locating the “public” API key on the Mailgun website. Under Domain Information for my validated Mailgun domain, I only see these options:

• State Active
• IP Address 209.61.151.224
• SMTP Hostname smtp.mailgun.org
• Default SMTP Login postmaster@mg.mydomain.com
• Default Password ################################ – Manage SMTP credentials
• API Base URL https://api.mailgun.net/v3/mg.mydomain.com
• API Key key-################################

When I enter this API Key in the plugin I get the 401 error. Is “API Key” the public key that I need for the plugin? Where is the key that I need? The instructions for finding it seem to be out of date.

https://wordpress.org/plugins/mailgun-email-validator/