Delivery Status Notification (Failure)

[tony84]

I am using gmail for my email, I have it linked up to use my own domain name and never really had any problems for years.
Today I have had 3-4 bounce back emails with the above title saying:

Message not delivered​ You're sending this from a different address or alias using the 'Send mail as' feature. The settings for your 'Send mail as' account are misconfigured or out of date. Check those settings and try resending. LEARN MORE

The response from the remote server was: 535 Incorrect authentication data​

I have clicked on the link but I do not really understand it. It has worked for years so unsure why it would not stop.

I dont suppose anyone can help?

Cheers.

 

[WESH.UK]

Hi Tony...

What did the tech support at Google say when you asked them about this?
That would be your ideal and best startinig point.

 

[Graham Tyers]

Without seeing the headers - impossible to say - even with, probably no different!

Two top guesses:

ipv6 - we are seeing lots of these where spf doesn't have ipv6 addresses. Check DNS and make sure you have v6 addresses for everything as well as v4. Different systems are adopting ipv6 at different rates.

DKIM - have you modified your signature or something and it includes something that is in the wrong charset. ( you may not have changed anything of course ) and other systems might have been updated. I recently had exactly as you describe start after updating a couple of servers. one system signs the body and then it doesn't check out at the other end because of a characterset mismatch.

Check your DNS with mxtoolbox.com . And feel free to send me an email to : [email protected] and I'll see if there's anything obvious.

Graham

 

[zigojacko]

Where have you got Gmail's SMTP configured to send email? Is this in your website - or somewhere else...?

It will be one of the following problems:-

1. Needs re-authenticating with username and password.
2. Needs to be sending email from the same email address as you are authenticating with (unless it is specified in an SPF record to be allowed).
3. Your email has been hijacked and someone is trying to send emails from another alias.

It may even be something to do with less secure apps or requiring an app password to authenticate (recently introduced and can be done from the security page in your Google account). The Google SMTP error messages are not always the most accurate or helpful.