It appears to be an unauthorized provider.
Addy aliases are temporary email addresses (aliases) that forward messages to their primary email account. This can help protect a user’s real email address from spam, unwanted marketing, or potential data breaches.
I have a business email account, a personal and a super user. Three.
I addy.io the personal with a separate domain, and give standard aliases to the business ones via the host (name@, info@, sales@, accounts@, …).
That’s two accounts I have to check every day. Not overwhelming and I’m old.