Host[] said: 451 4.3.0 Configuration error

Trying to catch-all email and send to an email cloudflare worker. No emails are being received. When I manually add a route to the worker, it works eventually.

When sending to a registered, enabled, catchall email pointed to a worker, the sending email gets an error:
host[] said: 451 4.3.0 Configuration error

We are making a dynamic catch for emails that will change overtime and call back to our webserver and db.

Think of a system like Zendesk that creates and deletes emails that route inbound emails to a database, but they can be deleted and created instantly. We were hoping to achieve this with Cloudflare email workers with a catchall so we don’t need to add and remove routes individually, but it doesn’t seem to work at all.

It works fine within the testing tool, but doesn’t receive live emails.

DNS was set weeks ago.

Any tips would be appreciated.

Hi there,

I don’t have the time to debug your worker, but I can make a suggestion that might solve your issue.

If all you want is a catch-all address, you might consider using Email routing. It basically creates the worker for you and allows you to have multiple emails being redirected to several destinations and have all the rest either dropped, redirected to an email or to a worker.

Take care.

Hey there, thanks so much for assisting here.

Unfortunately, if it wasn’t clear in my initial message that’s my bad, was late at night after hours of debugging. This is exactly what I am doing, the worker was created for me, I did setup the routing to send everything to the worker with the catch-all system that it created, and this error is the result of sending email to ANY email under this domain. The worker works fine in the testing tool, but it seems emails never hit Cloudflare’s servers, with the error returning to sending email servers being in my original post.

Hi there,

Oh. I didn’t realize that.
I’m sending you a PM for some additional information.

Take care.