Error testing Bounce email using SMTP from hosting provider - Other SMTP Server

Hi I’m running a hosted Mautic 4.3.1.
I’m having a problem that might not have to do with Mautic, or maybe, but would like to know if someone has had it and how it was solved.

Naturaly I searched through the forums, and have not found a post that would help to solve my case.

I have configured the email settings in Mautic and the “Test Connection” button gives a Success message.

However when I try the “Send Test email” button I get the following error message:

Expected response code 250 but got code “550”, with message "550 “The envelope e-mail address does not exist” "

This may be a problem with the provider or Mautic, is there anyone who can help and give a hint on how to overcome this problem ?

Additional information:

  • Previously to Mautic i was using Phplist and sending emails without problem using the same mail account.
  • In Monitored Inbox Settings when I click on the “Test connection and test folders” button I also get success message.
  • If I remove configuration from “Custom return path (bounce) address” in “Mail and settings” and all configurations from “Monitored Inbox Settings” and click the “Send Test email” button, it works and i get the test email.

Hi @peteredhair

You should try a simple email like as it is likely that your email does not support additional accounts by adding any valid string of characters after a “+” like the one you indicate:

Such “additional aliases” are usually supported by services such as Gmail, etc., but not necessarily by your domain.

I don’t think it’s a problem with Mautic but with your mailbox.


Thank you very much for your reply.
I also believe so.

However, while reviewing the configuration of the mailbox i found the following information where it refers to addressing with the + sign.

I’ll follow on the provider side as they are open to investigate, although not knowing, yet, the reason that triggers the problem.

Once again, thanks for replying.


Automatically Create Folders for Plus Addressing Automatically create a folder when this email address receives a message that uses plus addressing. For example, the system would place a message addressed to “” in a new folder called “plusaddress”.

Automatically Create Folders is selected, will try with not creating folders automatically with the + sign.

1 Like

Just to add a new note.
If an email is sent to the mails is received, in the bounce folder.

If you do what you say and your mail client does not support plus (+) addressing, as for example Gmail does, then this is the response you will get from the remote server when sending mail to that address:

550 <> sorry, no mailbox here by that name. #5.5.1