Trying to find help for 550 5.7.511 Access denied, banned sender

[AmityWeb2021]

I run a mail server for many business clients of mine. Microsoft have blocked our IP address, so we cant send to Office365 email addresses. I get a bounce back saying:

host cr-studio.mail.protection.outlook.com[104.47.21.36]
said: 550 5.7.511 Access denied, banned sender[12.34.56.78]. To request
removal from this list please forward this message to delist [at] messaging.microsoft.com. For more information please go to
http://go.microsoft.com/fwlink/?LinkId=526653. AS(1410)
[LO2GBR01FT022.eop-gbr01.prod.protection.outlook.com] (in reply to RCPT TO
command)

(I have changed my server IP above)

So I emailed delist[at]messaging.microsoft.com but they said:

"I do not see anything offhand that would be preventing your mail from reaching our customers for the following IP : (12.34.56.78)"

And gave me various links to pages with different support channels. One of them was to login to admin.microsoft or something, but I cant do that as I dont have an account. 

One of them was contact Microsoft support and they said its not to do with them, contact Office365. 

So I filled in a form on sender.office365.com and they replied:

"The IP address in question is not currently blocked in our system. Please refer to the email message you received from Microsoft and follow the steps it suggests." - which I have done, with the first email above!

I also filled in the form for emailing Live, Hotmail, Outlook.com and got no reply but dont think its to do with them. 

So I am very confused at the moment with all the different support channels, various Microsoft support telling me they cant see a reason for the block and then doing no more about it. 

I have no idea what the correct channel is and how to fix this, does anyone know? Its a bit of a shambles Microsofts side of it to be honest. 

[#2]

@AmityWeb2021 

Exaclty the same, my server is on linode. In the loop tryng to delist my server I got a message indicating that the ban is do to a rule by frontbridge.com

 Wrote an email to postmaster @frontbridge.com  but haven't received anything yet.

[#3]

That’s interesting. One of my customers (also on linode) forwarded me same email about frontbridge rules also. My customer has no idea who frontbridge is neither do I. I only saw such an email once.

[#4]

Has anyone got this issue on non-Linode servers? It seems everyone is on linode.

[#5]

@suportecw Microsoft have advised their servers currenly will not accept email from any Linode IP addresses.... 

[#6]

Could you explain this a bit more please? Where did you get this info? My other Linode servers send email ok (using a PHP mail script).

[#7]

Has anybody made any progress so far? I've been escalating this through all the channels I can possibly think of, but the issue is still there at our side.

[#8]

@timbertens One of my support cases has been escalated, and I have been asked for confirmation if I see the error only while sending emails to accounts hosted on Office 365 or even to other Microsoft domain accounts like Hotmail, Outlook, Live and MSN.

No news from Linode support either

If this issue takes a long time, I will consider moving the mail servers to another provider.

I'm redirecting mail traffic through an external smtp service for now.

[#9]

@Fede-9139  My linode and skyfibre ip addresses have been blocked randomly via MS plaforms. I can email my outlook account but can't email various custoemrs on Office365 ... the block is random by  MS mtas. I have Linode on the case for two weeks, have sent emails to delist@ms etc and lodged delist requesst via email and delist portal which says no ip is blocked. Also SDNS MS service shows all ips are good to go.

Can MS be so incompetant, is there a turf war on against Linode or is this the reason why we need to pursue anti-trust against MS for screwing us all?

Grrrr.

[#10]

Of course you are not alone in this, because this idiotic MS is the worst thing ever happend users on Internet!
Who will reimburse damage in milions ?
This idiots from MS ?
I don't think so.
They blocked my two IP twice in last one month!!!

There is no support mail, no nothing!
Only I could find Outllok twitter and I wrote them, but they do nothing!

[#11]

I think microsoft is so great that those who can actually order a solution to the problem don't even know what's going on.

Microsoft's postmaster support seems to be an endless bureaucratic hierarchy of contractors who do copy&paste every day.

I hope the escalations team are really human beings :)

[#12]

any forward movement on this front? I am getting a little desperate here as its starting to hurt not only my business but also my reputation as an email host - surely Microsoft can ban IPs with surgical precision rather than blocking entire IP ranges - I truly don't understand why we ALL have to suffer because of a couple of bad actors

[#13]

Hi, just reading this post, as I am having same issue since 24 December 2021, and using Linode 

@AmityWeb2021 

[#14]

Has there been any news on if there is a class action or anti-trust action being initiated over Microsoft blocking a competing hosting provider?

[#15]

@shirro 

I would expect some action from linode ... but the don't seems to care much ....

Waiting for Microsoft to understand and act is depressing ...

So my email traffic to domains managed by Microsoft is now redirected through outboundsmtp.com ... I can't see a better solution for now.

[#16]

@AmityWeb2021also affected by this, my mail server also running at Linode (Frankfurt in case this would matter). Issue started somewhen late December 2021. It was hopeless for me to get human contact at Microsoft. Tried to follow their generic workflow to delist at sender.office.com. It says my IP's not banned repeatedly. My IP scoring is also fine since years, I can't even remember the last DNSBL listing. Also created a Linode support ticket to get things going. This behavior is fully inacceptable. Full IP range blocks simply cannot happen, when the affected party is a normal web hosting provider.

[#17]

Hi all,
This problem may have been solved after the above messages, but it's recurred now, and I have two items of information I've learned so far in this subsequent bout which I wanted to share:

1) They are listing entire address blocks, so your individual IP address does not appear in their blocklist database. So then the automatic tools say that you're not blocked because you're not in the database. They're wrong, obviously, but this seems to be why.

2) That "frontbridge" stuff is some internal microsoft e-mail software objecting to your "Content-Type: message/delivery-status" e-mail header, or at least it seemed to be in my case. Be less correct about the e-mail headers (make it plain text) and I think you will not encounter this problem.

regards,
ajr