Undeliverable from some email servers. Think it's our end!

**DejaVu** · 4th October 2017

Can someone shed some light on this.
I think it's something to do with DNS and Authentication or perhaps even a Self Sign Cert for Exchange.
Do we need to prove it is us sending the email with confirmation the IP belongs to this exchange server.

All .gov.uk emails are doing this. On the whole, the rest seem to go through just fine.

Code:

From: THEMAN@tendringdc.gov.uk
Sent: Wednesday, October 4, 2017 2:46 PM
To: OUR EMAIL
Subject: Undeliverable: WHAT WE ARE TALKING ABOUT




mail.tendringdc.gov.uk rejected your message to the following e-mail addresses:


THE MAN (THEMAN@tendringdc.gov.uk)<mailto:THEMAN@tendringdc.gov.uk>


mail.tendringdc.gov.uk gave this error:
<OUREMAIL@US.COM>... Rejected - TRUSTmanager
Your message wasn't delivered due to a permission or security issue. It may have been rejected by a moderator, the address may only accept e-mail from certain senders, or another restriction may be preventing delivery.












Diagnostic information for administrators:


Generating server: CSSRV01.cliffords.local


THEMAN@tendringdc.gov.uk
mail.tendringdc.gov.uk #550 5.7.1 <OUREMAIL@US.COM>... Rejected - TRUSTmanager ##


Original message headers:


Received: from CSSRV01.cliffords.local ([IPv6 IP:2db4]) by


 CSSRV01.cliffords.local ([IPv6 IP:2db4%10]) with mapi id


 14.01.0438.000; Wed, 4 Oct 2017 14:45:31 +0100


From: OUREMAIL@US.COM>


To: <THEMAN@tendringdc.gov.uk>


Subject: RE: 


Thread-Topic: WHAT WE ARE TALKING ABOUT


Thread-Index: AdMNLmul6FPuHD5dQTKq+ZprhBtzIAAAPIRAA438AdADHOZ1MAAEFJLwACiaZVAEthgggAAAhcbwAGulocA=


Date: Wed, 4 Oct 2017 13:45:30 +0000


Message-ID: <30141C11CFD4C74785766A88E2770C7D0145A603A5@CSSRV01.cliffords.local>


References: <D0341BE740848445B623A770D250F0B66F8EDDEA@TDCCTHEXG001.tendringdc.gov.uk>


 <D0341BE740848445B623A770D250F0B66F8EDE07@TDCCTHEXG001.tendringdc.gov.uk>


 <D0341BE740848445B623A770D250F0B66F9015F1@TDCCTHEXG001.tendringdc.gov.uk>


 <D0341BE740848445B623A770D250F0B66F913DCA@TDCCTHEXG001.tendringdc.gov.uk>


 <30141C11CFD4C74785766A88E2770C7D01459DBAD2@CSSRV01.cliffords.local>


 <D0341BE740848445B623A770D250F0B66F9140FE@TDCCTHEXG001.tendringdc.gov.uk>


 <D0341BE740848445B623A770D250F0B66F93C2EF@TDCCTHEXG001.tendringdc.gov.uk>


 <D0341BE740848445B623A770D250F0B66F93C307@TDCCTHEXG001.tendringdc.gov.uk>


In-Reply-To: <D0341BE740848445B623A770D250F0B66F93C307@TDCCTHEXG001.tendringdc.gov.uk>


Accept-Language: en-GB, en-US


Content-Language: en-US


X-MS-Has-Attach: yes


X-MS-TNEF-Correlator:


x-originating-ip: [192.168.1.105]


Content-Type: multipart/related;


        boundary="_008_30141C11CFD4C74785766A88E2770C7D0145A603A5CSSRV01cliffo_";


        type="multipart/alternative"


MIME-Version: 1.0

The only obvious thing here is our local domain is being sent via the Email Headers along with the original internal IP Address.

Would this make it fail because "TrustManager" doesn't like it?
Is a Self Signed Certificate needed somewhere?
Do I need to put some sort of 'this IP belongs to this domain/email address' on sending each email?

Only had this pain in the arse since transferring to Virginmedia's new awesome super dooper Business account that CANNOT offer a fixed IP Address at the moment and we've had to implement Dynamic.
Fucking one headache after another with this shit! Including requesting the Dynamic IP Address to be lifted from 14 Blacklists!! FFS!

HELP!