Show original error message created by recipient's server, when email cannot be sent

When a mail is refused by the recipient’s server we only get a generic notification that looks like this:

Email cannot be sent to recipient_AT_domain from your alias alias.xyz_AT_simplelogin
This might mean recipient_AT_domain
is not a valid email address, or
doesn’t exist, or
its mail server refuses your email.

But at this stage you still don’t know, what the actual error was.

  • Is the recipient’s mailbox full (quota exceeded)?
  • Maybe you had a typo in the email address?
  • maybe something else went wrong?

The recipient’s server actually generates a specific standard error code and sends an according message back to SL (but SL hides the original error message somewhere and displays only a generic message - the one mentioned above). The original error code is something like:

550-5.1.1 user unknown
552 storage exceeded

and THIS code/error message is the one, I’d like to see somewhere. Maybe a button like
[see error details] just below the generic text?

Seeing these error details would seriously help solving issues with bounced emails.