Why did inbound mail bounce?

Mail to a reserved Gnesi address is accepted only when the worker exports an email handler.

Mail to name@gnesi.io is received by Cloudflare Email Routing and handed to the Gnesi worker. The worker stores it on that person's inbox when the local-part is reserved.

If the live worker exports only fetch and not email, Cloudflare rejects the recipient as address not found. The sender gets a bounce. That bounce does not become a message later. Send it again after the worker is accepting mail.

Unknown local-parts stay rejected. Gnesi is not an open relay.

Outbound invites use the Email Service binding from hello@gnesi.io. They are a different path from inbound routing. An invite can arrive in Gmail while a reply to you@gnesi.io still bounces, if the worker is not accepting inbound mail.