Slow delivery of carbon copied of some emails

[#1]

Since Wednesday (I think), the carbon copy of some emails I send is taking a long time to arrive (several days) although the main recipient(s) seem to receive them.
This could of course not be anything to do with plusnet but the header trace shows that they sit for a long time on the plusnet end before going to namecheap. Note that other emails to me, coming via namecheap, seem to go fine. I have also checked to see if there is a consistency of the host involved (either at plusnet or namecheap) but there isn't. I attach one email in case it helps.

[#2]

If I had to guess, I'd say the server at registrar-servers.com is deferring connection attempts from our avasout servers. Might be an idea to get in touch with them and see if they can spot anything in their inbound logs. If you don't get any joy, we can try sifting through our outbound logs but if I'm right, it's probably them that will need to make changes.

[#3]

The spf record for your .me.uk domain seems to have been set to authenticate mail only from avasout05; the problem one you attached was sent via avasout06 which may be the cause of the delay. You could try replacing the txt record with

v=spf1 mx include:madasafish.com

.. which hopefully will eliminate the problem.

[#4]

Good spot!

[#5]

Thanks for your advice.
I have implemented it and I have had no problems since.
Looking at emails, I can now see that the Received-SPF and X-SPF-Result fields show that the change is effective in the sense that plusnet hosts other than avasout05 are now permitted senders

[#6]

Glad to hear that change fixed the problem.