MTA has a negative reputation

[Brandon]

MTA issue:

• Two separate mail servers, hosting different domains, sitting on the same /24 ip range.

• rDNS, SPF, DKIM all 100%

• Incoming mail working fine

• Outgoing mail to most recipients also fine

• Sending to certain servers returns "5.7.1 The message has been rejected because the sending MTA has a negative reputation"

Ok, so the ip's are in a blacklist, right?
But MXToolbox & Talos Reputation lookups are clean

Contacted Liquid Telecoms (one of the ISP's in question), they won't help as I am not their customer

I am trying to work with the mail recipients to log support calls directly, however most of them are small SME's that have outsourced pay-per-hour IT support - and are not too keen paying to resolve the issue of receiving mails from one sender.

TLDR : anybody else have success in resolving "....sending MTA has a negative reputation"?

(as helpful as Windows 10 BSOD "Something went wrong")

 

[Adenoid Hynkel]

How much mails do these mail servers relay per hour?

 

[Brandon]

Quite low
<=100 per day.
A peak hour can have about 30.

Not used for marketing, newsletters or spam.

 

[infscrtyrisk]

There are many different rep lists, with varying reasons and weightings. Some are good, others quite anal. What is your MTA's public IP addy?

 

[Brandon]

Not chancing posting that on a public forum, will PM to you...

Edit: you're PM's are turned off!

 

[Adenoid Hynkel]

Quite low
<=100 per day.
A peak hour can have about 30.

Not used for marketing, newsletters or spam.

Have you been on the same IP for a while or have you just recently switched to them? Drop me a pm with one of the IPs

 

[Brandon]

Have you been on the same IP for a while or have you just recently switched to them? Drop me a pm with one of the IPs

You got PM.
Servers are currently run over VPN's with static IP's and rdns.
This happened about 3 months ago with the move to fibre with a dynamic ip, the VPN's were used as a work-around to this and also to allow these two servers to run on a single connection.

There is probably some secret list that's got those ip's listed. Would just be helpful if the isp's disclose that so the problem can be sorted. Their 554 may as well return "fsk u!"

 

[infscrtyrisk]

Not chancing posting that on a public forum, will PM to you...

Edit: you're PM's are turned off!

Yep, it is. I'll turn it on specially for you!

 

[Brandon]

Yep, it is. I'll turn it on specially for you!

Thanks
You got PM!

 

[infscrtyrisk]

Replied. Good luck, hope that you get it sorted.

 

[Brandon]

I have requested delisting as per the PM's.
Will check back in a few days to allow for the changes to be processed/propagated...

Thanks again for the help!