I should also mention that the email that’s shown there, though i know it, it’s not the email that’s seen in my Sendgrid “Single Sender Verification” list.
I noticed that the sender email was set to: admin@mywebsite.com (mywebsite.com is a placeholder). I never set up an admin email, so I’m not sure why it was there.
To resolve this, I went to my domain host and created an email redirect for admin@mywebsite.com so that any emails sent to that address would be forwarded to me.