Richard Dale

This continues to happen approximately once a month for us.

It's not a pleasant situation when the customer things we're ignoring them but the email is stuck on a mail queue somehwere with zero notification to us that it's delayed.

Zendesk need to implement custom outbound SMTP servers to fix this problem.  If the mail is being delayed, at least we know since it's our own mail server.

This has been raised as a support issue previously, but we don't have a high volume of support mail and it typically resolves a few days later.

We are currently experiencing about 1 failed email to Yahoo per month (out of maybe 5-10 per month to users of Yahoo) which is a high percentage of failures.

 

This is urgently required.

We've had a situation twice in the last month where emails to _all_ Yahoo users were delayed due to Yahoo temporarily deferring emails due to spam complaints.

The real problem here is that we do NOT receive any such reports until some DAYS afterwards, after it has been sitting in the queue on the Zendesk SMTP server.  So we have a situation where a) we think the support issue has been resolved and b) the user thinks that we are ignoring them.

Using our own mail servers allows us to at least monitor any outbound mail issues - plus, being a mail server only we use on a dedicated IP address, means our IP address's reputation is not an issue.

An example of this is below.

Timeline:
Support response sent Sun, 14 Nov 2021 14:16:48 +0000
Bounce message received: Fri, 19 Nov 2021 14:36:14 +0000

This is the mail system at host deferred3.pod25.apne1.zdsys.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<XXXXXXX@ymail.com>: host mta7.am0.yahoodns.net[67.195.228.94] said: 421 4.7.0
    [TSS04] Messages from 103.151.192.18 temporarily deferred due to unexpected
    volume or user complaints - 4.16.55.1; see
    https://postmaster.yahooinc.com/error-codes (in reply to MAIL FROM command)

Scenario for the last week:  All Zendesk replies to users with @yahoo.com or @ymail.com have been delayed then (after 5 days) bounce back to us.

Bounce messages are coming back fro multiple Zendesk SMTP servers - with error codes relating to security/spam type of conditions.

Our own mail server has a high reputation, dedicated IP address with no bouncing issues for years.

If we could use our own SMTP server for outbound replies this would avoid these sorts of issues.