Email Workers - message.setReject repeated delivery attempts

I have in my email worker a Try - Catch where if my primary email rejects the message, I have an additional Try - Catch for my backup address:


try {
    await message.forward("[email protected]");
}            
catch (e) {
    try {
        await message.forward("[email protected]");
    }            
    catch (e) {
        message.setReject(e.message);
    }
}

When testing the backup Catch by intentionally sending an email from Outlook that is too large (so that it will be purposfully rejected by my backup address), delivery is re-attemped many times.

  1. Is there something I can do to prevent these repeated attempts at re-delivery, like a custom hard-bounce reject message that will tell the server to stop further attempts?
  2. Is setReject necessary if I have a backup email? I have a telegram bot that informs me when a message is rejected so I don’t need to see it in the Activity Log. My question is more about - is it important for me to send the reject to the reciepient?

Update: Looks similar to this. I was also sending from Outlook.