Email explanation please

[#1]

As my email was sent up years ago, things were much simpler. However I have met the Gmail problem but do not understand which part of the routing is incorrectly set.
I have a Plusnet username, hence email is xxxxx@username.plus.com. My email clients are set up to show a domain name handled by ionus. Is the problem with client settings, Plusnet settings or ionus domain name settings. I realise there is a thread about this, but quite frankly, it goes so deep when first of all I need to identify which part of the routing I need to look at.

[#2]

@briston My email clients are set up to show a domain name handled by ionus

Some questions to establish exactly how you are setup, so we can advise what needs configuring.

So effectively you are sending & receiving mail using your domain address , yes ?

The domain is registered at Ionos , yes ?

Are sending mail using the Plusnet server , relay.plus.net ?

How do you receive mail addressed to the domain email address, is it forwarded to your Plusnet email address xxxxx@username.plus.com. ? by Ionos ?

[#3]

I'll try to answer in the order you asked.
Yes, all mail is sent and received to look like name@domainname.co.uk
The domain name is registered at ionus
Yes email is sent via relay.plus.net
Yes email is forwarded to xxxx@username.plus.com by ionus

As an addition, I have contacted ionus. They are well aware of the Gmail problem. If you purchase a domain now that set the SPF correctly. This is where I totally get lost. Because this domain was registered a fair while ago but only b was the SPF not set to deal with the new requirements of Gmail but other 'soft' and 'hard' settings of something were changed. Apparently they can dig deeper but considering the changes they have made, I'm wondering if I am barking up the wrong tree and although there are or were problems at the ionus settings are there others.

[#4]

@briston 

Ok, thanks. So in a nutshell, the problem is that gmail is inisting on either SPF and/or DKIM for any domain sending email to gmail accounts.

An SPF record defines which email servers are authorised to send email for your domain. In your case , you are sending via the PLusnet servers, so your SPF record needs to define those servers as authorised. Your domain is registered at Ionos but if you were to use  the standard IONOS record, that would define their servers, which is not what you want.

If you follow this guide here https://www.ionos.co.uk/help/domains/configuring-mail-servers-and-other-related-records/using-ionos-... BUT select the SPF(TXT) option that is detailed as 'freely define who is legitimised as sender of your emails'  and enter the text below

v=spf1 a mx include:_spf-internal.plus.net include:_spf-internal2.plus.net ~all

 That should define the Plusnet servers as senders of email for your domain.

You can check for the existence of the correct SPF record for your domain here https://mxtoolbox.com/. Enter your domain name and click MX Lookup button , the buuton should now have a dropdown menu, use that to select SPF record lookup and click the button. That should display your SPF record.

Hope that makes sense

[#5]

Add record

TXT
@
"v=spf1 include:_spf-eu.iono

Please excuse is I say that as for making sense, not a lot. But that's not your fault. Anyway. So I take it you say the record at ionus pasted above, needs to be edited to what you say?

[#6]

@briston Anyway. So I take it you say the record at ionus pasted above, needs to be edited to what you say? 

You are correct, it needs changing to the one I posted above OR to allow both the IONOS and Plusnet servers you could change it to

v=spf1 a mx include:_spf-internal.plus.net include:_spf-internal2.plus.net include:_spf-eu.ionos ~all

[#7]

First indications show success!