Email issue sending to @Gmail addresses

When I send an email (my outgoing server is mailhost.zen.co.uk) to any @Gmail address, I get an error like :

" This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

[email protected]
host gmail-smtp-in.l.google.com [108.177.15.26]
SMTP error from remote mail server after pipelined end of data:
550-5.7.26 This mail has been blocked because the sender is unauthenticated.
550-5.7.26 Gmail requires all senders to authenticate with either SPF or DKIM.
550-5.7.26
550-5.7.26 Authentication results:
550-5.7.26 DKIM = did not pass
550-5.7.26 SPF [savamac.co.uk] with ip: [212.23.1.20] = did not pass
550-5.7.26
550-5.7.26 To mitigate this issue, please visit Gmail's authentication guide
550-5.7.26 for instructions on setting up authentication:
550 5.7.26 https://support.google.com/mail/answer/81126#authent... a12-20020adfe5cc000000b0031fb9ea076bsi3318228wrn.493 - gsmtp "

How do I resolve this ?

In reply to a post by savamac:

How do I resolve this ?

Assuming you are sending using a personal domain name (savamac.co.uk), you need to add an SPF record to your DNS entry for your domain. SPF is BASIC anti-spam required by all the big email organisations now, and most corporates.

If you are using a zen.co.uk email address, then raise a ticket.

Some guides on SPF:
https://support.google.com/a/answer/10684623?hl=en

https://www.techtarget.com/searchsecurity/tutorial/H...

Edited by jchamier (Tue 24-Oct-23 14:30:57)

I had this with my personal domain emails earlier in the year. Following some Googling I changed something, don't remember what, on my domain host, Ionos in my case, and fixed it.

In reply to a post by savamac:

When I send an email (my outgoing server is mailhost.zen.co.uk) to any @Gmail address, I get an error like :

" This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

[email protected]
host gmail-smtp-in.l.google.com [108.177.15.26]
SMTP error from remote mail server after pipelined end of data:
550-5.7.26 This mail has been blocked because the sender is unauthenticated.
550-5.7.26 Gmail requires all senders to authenticate with either SPF or DKIM.
550-5.7.26
550-5.7.26 Authentication results:
550-5.7.26 DKIM = did not pass
550-5.7.26 SPF [savamac.co.uk] with ip: [212.23.1.20] = did not pass
550-5.7.26
550-5.7.26 To mitigate this issue, please visit Gmail's authentication guide
550-5.7.26 for instructions on setting up authentication:
550 5.7.26 https://support.google.com/mail/answer/81126#authent... a12-20020adfe5cc000000b0031fb9ea076bsi3318228wrn.493 - gsmtp "

How do I resolve this ?

As a Microsoft partner I can confirm that Both Yahoo, AOL, Gmail and other platforms are now requiring SPF as minimum and DKIM is also required, if you need advise on DNS changes and you are a company let me know and I can put you in touch with the team who can help out.

There a 3 things which need to have look at SPF, DKIM, DMARC.

It recomend that get working in this order.
1) SPF (Sender Policy Framework)
2) DKIM (DomainKeys Identified Mail)
3) DMARC (Domain-based Message Authentication Reporting Conformance)
needs both SPF DKIM set correctly and working.

What is SPF? https://www.youtube.com/watch?v=TFFMT_8uMEA
What is DKIM? https://www.youtube.com/watch?v=5fjmPQgqdzw
What is DMARC? https://www.youtube.com/watch?v=XrFWhA0VdO8

In reply to a post by RR_The_IT_Guy:

In reply to a post by savamac:

When I send an email (my outgoing server is mailhost.zen.co.uk) to any @Gmail address, I get an error like :

" This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

[email protected]
host gmail-smtp-in.l.google.com [108.177.15.26]
SMTP error from remote mail server after pipelined end of data:
550-5.7.26 This mail has been blocked because the sender is unauthenticated.
550-5.7.26 Gmail requires all senders to authenticate with either SPF or DKIM.
550-5.7.26
550-5.7.26 Authentication results:
550-5.7.26 DKIM = did not pass
550-5.7.26 SPF [savamac.co.uk] with ip: [212.23.1.20] = did not pass
550-5.7.26
550-5.7.26 To mitigate this issue, please visit Gmail's authentication guide
550-5.7.26 for instructions on setting up authentication:
550 5.7.26 https://support.google.com/mail/answer/81126#authent... a12-20020adfe5cc000000b0031fb9ea076bsi3318228wrn.493 - gsmtp "

How do I resolve this ?

As a Microsoft partner I can confirm that Both Yahoo, AOL, Gmail and other platforms are now requiring SPF as minimum and DKIM is also required, if you need advise on DNS changes and you are a company let me know and I can put you in touch with the team who can help out.

GMail has been requiring it for several years now.

As a Microsoft partner I can confirm that Both Yahoo, AOL, Gmail and other platforms are now requiring SPF as minimum and DKIM is also required, if you need advise on DNS changes and you are a company let me know and I can put you in touch with the team who can help out.

DKIM is not *required* by anyone at present as such, but does help in many *but not all* cases. SPF on the other hand is pretty much a minimum required, especially for GMail if you want to have your mail delivered.

GMail has been requiring it for several years now.

Not quite several years, but in the last 12-18 months they've ramped it right up for sure.

Sorted : SPF was set up and I got "Authenticated SMTP" added to my domain - problem solved.

In reply to a post by therioman:

Not quite several years, but in the last 12-18 months they've ramped it right up for sure.

Gmail has been honouring DMARC reject for probably over 5 years now and has always had far superior intelligence when it comes to SPF/DKIM without a DMARC record. Same cannot be said for Microsoft who have only the past month or so started honouring it properly.

In reply to a post by therioman:

As a Microsoft partner I can confirm that Both Yahoo, AOL, Gmail and other platforms are now requiring SPF as minimum and DKIM is also required, if you need advise on DNS changes and you are a company let me know and I can put you in touch with the team who can help out.

DKIM is not *required* by anyone at present as such, but does help in many *but not all* cases. SPF on the other hand is pretty much a minimum required, especially for GMail if you want to have your mail delivered.

GMail has been requiring it for several years now.

Not quite several years, but in the last 12-18 months they've ramped it right up for sure.

You've jogged a memory now. Having thought a bit more about it I think it might have been something relating to IPv6. I think that GMail switched to preferring IPv6 instead of IPv4 (or possibly when I moved from PlusNet back to IDNet and gained IPv6 support) but then complained if you didn't have rDNS set up for your email server's IPv6 address.

The solution was to either disable IPv6 for your mail server or (as I presumably did) do a full IPv6 configuration.

Edited by Andrue (Fri 27-Oct-23 21:30:37)