Send email using parameter as Password: authentication required

Hi Team,

We are getting below error message as "[Warning-Duplicati.Library.Modules.Builtin.ReportHelper-ReportSubmitError]: Failed to send message: MailKit.Net.Smtp.SmtpCommandException: 5.7.0 Authentication rejected " when setup send email to test, the MTA will accept password authentication required, no SSL we configured as follows. Please help us the parameter to add.



since you are not using Tls, it is trivial to trace the exchange with the mail server with a tool like tcpdump. Did you do so ? if yes, did you try to reproduce the exchange using a tool like telnet (or nc) ?

You can follow the mail exchange also with Using Duplicati from the Command Line - Duplicati 2 User's Manual

Did you consider this post:


Our provider not using exchange they are using MDaemon.

Normally we use a parameter as Authentication method as Password.

Please help us to set this up.

Did they tell you to use port 25 as you did? Ordinarily port 587 would be a client submission port.
Which SMTP port should I use? Understanding ports 25, 465 & 587 (see advice against port 25)

which can be done either from true CLI e.g. Windows Command Prompt, or Commandline in GUI.
Be careful not to post the whole thing, as you may post your authentication (if that matters to you).

Key points would be what authentication the servers accepts, e.g.


C: AUTH ... is the client authentication showing which it used, and its value (don’t post the value).

S: 235 Authentication successful is what you’d like to see, and seemingly you didn’t get that.

Nobody but your provider can say exactly how they want this to be set up. Please find out and tell us.
Beyond that, you’ve been given help but you need to actually do some work to diagnose the problem.

Did you try to add ? That was the cause in the linked post, and it is not in your list of flags.

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Interesting observation. My ISP puts up with the default. I’m surprised any that complain complain then.
The transcript I’ve been encouraging looking at doesn’t even get the From line until after authentication.

  --send-mail-from (String): Email sender
    Address of the email sender. If no host is supplied, the hostname of the
    first recipient is used. Examples of allowed

Mail Sender <sender>
Mail Sender
    * default value: no-reply

While here, I’ll mention that you might be exposing your credentials to anybody watching the network.
I’m not sure you want that, but I don’t know your network either, which might also affect port question.

220 ESMTP MSA; Fri, 16 Jun 2023 09:03:10 +0200

You omitted two of the three requested lines, but the important one is server response to the AUTH.
It’s probably on the next line, but seems unlikely to be a 235 for success. Status Codes lists options.

These are remainging status codes 250-8BITMIME
250 SIZE

You might be showing lines above. I want the line probably right after the AUTH. Redacted example:

S: 250 SIZE 52428800
C: AUTH PLAIN <redacted>
S: 235 Authentication successful

S means server message. C is the client, so Duplicati. When Duplicati does AUTH, what’s response?
Click on the Status Codes link if you want to see what they might be. Possibly got 400 or 500 series.

Hi, this are the response am getting.

This shot looks even worse, but it explains why your AUTH didn’t get a response. It was never sent.
What is this screenshot from such that the C: and S: prefixes are not seen? Is this a manual telnet?

The 220 at top would be by server at initial connect. The ehlo (often EHLO) would be the client data.
The 250 server responses are informational. What’s supposed to send the client AUTH in this case?

While it’s possible to manually make/send AUTH PLAIN, the better test is to use Duplicati send-mail,
mentioned earlier, and that can be run in many ways e.g. GUI Commandline, also mentioned earlier.

This begs the question of how you usually run Duplicati. Is it a GUI job or command line? If the latter,
you must also make sure that you quote things that need quoting, e.g. if there’s an embedded space.

Hi, thanks for your response appreciate i checked with our provider they whitelist our duplicati ip for authentication now it’s fine, thanks.

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