Issue Cant send email to hotmail, outlook. Only Gmail and custom domains is ok

[dxflw]

Hi to all,

I have vps in contabo with CentOS Linux 7.4.1708 (Core)‬ and plesk web admin edition 17.5.3.
With my emails accounts of 4 domains when i sent email to hotmail or outlook is not delivered and i get a message of:
Undelivered Mail Returned to Sender from MAILER-DAEMON@vmi100902.contabo.host
This is the mail system at host vmi100902.contabo.host.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<edevil@hotmail.gr>: host eur.olc.protection.outlook.com[104.44.194.236] said:
550 SC-001 (SNT004-MC10F2) Unfortunately, messages from 173.212.214.21
weren't sent. Please contact your Internet service provider since part of
their network is on our block list. You can also refer your provider to
Troubleshooting. (in reply to MAIL
FROM command)
Reporting-MTA: dns; vmi100902.contabo.host
X-Postfix-Queue-ID: DD269207C77C5
X-Postfix-Sender: rfc822; no_reply@katharmata.net
Arrival-Date: Wed, 22 Nov 2017 16:50:01 +0200 (EET)

Final-Recipient: rfc822; edevil@hotmail.gr
Original-Recipient: rfc822;edevil@hotmail.gr
Action: failed
Status: 5.0.0
Remote-MTA: dns; eur.olc.protection.outlook.com
Diagnostic-Code: smtp; 550 SC-001 (SNT004-MC10F2) Unfortunately, messages from
173.212.214.21 weren't sent. Please contact your Internet service provider
since part of their network is on our block list. You can also refer your
provider to Troubleshooting.

 

[Bitpalast]

Your host's IP is blacklisted by Microsoft. I has probably sent or is still sending spam messages to Microsoft hosted mail accounts.

Check status here: Sign in to your Microsoft account

Apply for delisting here: https://support.microsoft.com/en-us...productkey=edfsmsbl3&ccsid=635648144919316674

Do not apply for delisting when your host is still sending spam.

 

[dxflw]

Thank you.

How to find wich email is sending spam? Should i delete all email adresses before sending to MS?

 

[Bitpalast]

A good starting point to find out from where spam is being sent is the maillog at /var/log/maillog or /var/log/mail.log.

It is not necessary to delete any mailboxes.

It might not be enough to delist at MS. Check MultiRBL.valli.org - Blacklist, Whitelist and FCrDNS check tool with your host's IP address to find out where it is listed.

 

[dxflw]

if i buy a new ip will be fixed?

 

[Bitpalast]

For a few minutes, yes.

 

[dxflw]

Actually i don't use email for my domains, i have a friend who have 3 domain and 3 emails/per domain. I asked hime if he's use cracked software in their pc and they say yes and allot.

I have download the maillog from /var/log/maillog(FILE) but i can't understand. if you can help me about i will be very appreciate about.
My solution what i think is:
1. format the pc of this guy, new clean installation of windows 10
2. Change in the server the emails passwords (after format the pc)
3.. Contact MS for delist

Will this steps fix the problem?

 

[Bitpalast]

It can be a valid approach if the mail is sent from the computer. It can also be sent from a malware on one of the websites on the web server.

 

[dxflw]

I have scan the server via the virustotal extension for plesk and only one domain is showing inffected.

Scan report for http://ds-pisoderi.gr/site/wp-content/plugins/redirection/locale/sample2.html at 2017-11-22 17:34:38 UTC - VirusTotal

I have deleted the path of the wp plugin wich was infected but in the rescan is still shoing the issue..

What is wrong?

 

[Bitpalast]

When a Wordpress website is infected with a malware, it is normally insufficient to remove the visible parts of the malware, because the backdoor mechanism will remain in other code parts. Very often, a reinstallation of the complete website including all files (and omitting the bad plugin of course) is required.

 

[dxflw]

Is there any server component to do the work? SpamAssassin will do that? any extension?

 

[Bitpalast]

No.

 

[dxflw]

I have found and done this:

from this url: How to find the source of spam
Will that stop the spam?