PlusNet bouncing inbound emails?

[#1]

Hi - I have several friends on PlusNet who have recently been failing to receive inbound email messages from me to their <name>@<mailbox>.plus.com mailboxes. I have been emailing these friends on PlusNet on a regular basis without any problems until recently. I have read  a few relevant posts on this forum but have not identified how to investigate/fix this beyond the tests I have listed below.

My sending email address is <mailbox>@<domain>.me.uk

My email is hosted by '4uHosting' (I can provide mail server ID and IP address via private message if required)

Please could anyone advise whether PlusNet could have any other checking on inbound email in place that could be blocking/bouncing mail from my mail address/server. Ie could PlusNet be rejecting mail from my '…..me.uk' domain or from my mail '<name>.4uH.net' host server? 

If, so please could you advise what I need to do to get this un-blocked? As a non PlusNet Customer, I can't find any route via the PlusNet website to raise this issue.

Thanks - Paul Kelley

I have tried the following without success to try to narrow down the problem:

- Confirmed with my ISP ('4uH')  that my sent messages to PlusNet mailboxes are not being blocked and not being spam filtered by 4uH

- Confirmed with 4uH that their mail server is not on any known RBLs

- Confirmed with my friends on PlusNet that they have not knowingly been rejecting my emails as Spam.

- Sent simple test messages to PlusNet mailboxes that include a subject field and a very simple txt only message and no attachments. These also bounced by PlusNet, suggesting the problem is not in the content of my emails.

- Confirmed that other people (not themselves on PlusNet and not on 4uH) are able to send OK to these PlusNet mailboxes, suggesting the PlusNet mailboxes are currently active.

- Confirmed that these PlusNet mailboxes are still able to send email to me on my '<mailbox>@<domain>.me.uk' address.

- Sent messages to PlusNet mailboxes from different sending email clients (inc MSOutlook/Win10 and (Sony) SmartPhone) - all of which were bounced.

- The bounce messages were:

--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:

--<name>@<mailbox>.plus.com

--all hosts for '<mailbox>.plus.com' have been failing for a long time (and retry time not reached)

-The bounce 'details' text attachment was:

--Reporting-MTA: dns; <4uH mail server>

--Action: failed
--Final-Recipient: rfc822;<name>@<mailbox>.plus.com
--Status: 5.0.0

[#2]

The first thing I would try in these circumstances is to get some of these friends to send you an email and reply to it.  That would eliminate the possibility of some sort of corruption, visible or otherwise, in your list of contacts.

If that fails I would say it is safe to infer you are on some sort of blacklist, despite what your email provider has told you.

[#3]

Thanks very much. I've tried replying as you suggested and my messages are still being bounced. I agree re somehow being blacklisted but as I have messages being bounced from multiple Plusnet addressees I assumed this implied Plusnet (rather than addressees themselves) would be doing the bouncing? My Plusnet friends are still able to send emails to me and I'm not having other (non Plusnet) sent emails bounced.
If I look at the source for header in the bounce messages, should I be able to identify who's doing the bouncing?