SMTP Authentication

[tonymitch]

I am receiving the message below when attempting to send an email to one specific address. No problems with other addresses.

Have ensured POP accounting setings are as advised in other posts, including activating SMTP Authentication. Are there other setting I need to change?

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The original message was received at Wed, 13 Oct 2021 18:13:35 +1100 from 110-174-101-26.tpgi.com.au [110.174.101.26]

This message was generated by rpt-cro-mail01.tpgi.com.au

   ----- The following addresses had permanent fatal errors ----- <xxx.xxxxxx@dvesolutions.com.au>

    (reason: 550-Please turn on SMTP Authentication in your mail client. )

   ----- Transcript of session follows ----- ... while talking to dvesolutions.com.au.:

>>> DATA

<<< 550-Please turn on SMTP Authentication in your mail client.

<<< 550-rpt-cro-mail01.tpgi.com.au [60.241.0.56]:41764 is not permitted to relay <<< 550 through this server without authentication.

550 5.1.1 <xxx.xxxxx@dvesolutions.com.au>... User unknown <<< 503-All RCPT commands were rejected with this error:

<<< 503-Please turn on SMTP Authentication in your mail client.

<<< 503-rpt-cro-mail01.tpgi.com.au [60.241.0.56]:41764 is not permitted to relay <<< 503-through this server without authentication.

<<< 503 Valid RCPT command must precede DATA

[david64]

Hi @tonymitch . 

550 5.1.1 <xxx.xxxxx@dvesolutions.com.au>... User unknown 

The 5.1.1 error means Bad destination mailbox address.

The mailbox specified in the address does not exist. For Internet mail names, this means the address portion to the left of the "@" sign is invalid.

Can you verify the destination username?

[tonymitch]

Thanks David,

The email address/username is valid - I have received emails from this address, but can't send to it.

Any other suggestions?

[david64]

@tonymitch . What email client do you use?

Have you been able to send to this address before? Or, is it a new address you haven't sent to before?

Email postmaster@tpg.com.au with this problem. There might be setup problem between TPG and the other domain.

[tonymitch]

I use Outlook and have not been able to send to this address. That is, it is a new address I have been trying to email for a month or two. I'll send a message to postmaster@tpg.com.au. Thanks for your help.