Microsoft and google network are the most widely used email services, If your mail are rejected by these ISP then one cannot simply ignore or wait out for things to work again as they won’t.
Today we would discuss ways to improve delivery issues for Microsoft Network which include outlook.com, live.com, hotmail.com and msn.com email accounts. We would be covering fix for rejection received due to sending server IP reputation, If your scripts are compromised and generating spam sent to hotmail or you are unlucky and sharing email service with spammy users then Email IP from which your email is dispatched will be blocked by Microsoft.
They also do not like bulk mailing and there are volume cap for legitimate bulk mailing as well thus anything above 400-500 mails per hour can get your email IP blocked. If you are more fortunate one then entire IP range will be blocked so your IP neighbors will also pay for your email server deeds.
Now to get down to it this will be the general error you will receive as bounce back mail from hotmail if your email is rejected due to bad reputation of your mail IP.
SMTP error from remote mail server after MAIL FROM:<test@somedomain.com>
SIZE=1844: 550 SC-001 (COL004-MC5F15) Unfortunately, messages from "Your Mail IP" weren't
sent. Please contact your Internet service provider since part of their network
is on our block list.
Here “Your Mail IP” is the actual IP of your mail server which is blocked. Sometimes users get confused and consider Website or Webserver IP as mail IP but most of the time Email sending IP entirely different from website IP. It can also be checked by viewing full header of email.
While checking blacklist or requesting removal from ISP block make sure to quote the correct IP.
Step 1:
First you need to ensure that your script plus server is clean and no longer generating spam. Locate source of spam by checking mail server logs for example if using exim check exim mainlog at /var/log/exim_mainlog
If using cPanel do check “Mail Delivery Logs” as well as “Mail Queue Manager” in WHM which is convenient allowing you to catch spam sending user or script fast. If you do not have root access to server then you need to contact your hosting provider to help you out stopping spam generation.
[AdSense-B]
Step 2
Make sure mail IP is clean at major RBL which you can check at
http://mxtoolbox.com/blacklists.aspx
Microsoft will reject your request to mitigate mail IP if your mail IP is listed at any major RBL
Step 3
Setup SPF and DKIM for your domain.
Typical SPF TXT record will be
"v=spf1 ip4:Mail Server IP ?all"
if using cPanel SPF can be setup with this command
/usr/local/cpanel/bin/spf_installer cpanel_user
DKIM can be setup using this command
/usr/local/cpanel/bin/dkim_keys_install cpanel_user
Step 4
Setup PTR reverse DNS record for your mail IP, this will be setup by your hosting provider.
Please make sure PTR record resolve to actual mail IP for example if PTR record for mail IP is setup as mx91.somehost.com then mx91.somehost.com A record must point back to mail IP.
Step 5
Now its time to contact Microsoft support as your house is in order, Please use this link which will open sender delivery information form
http://go.microsoft.com/fwlink/?LinkID=614866
Fill out the form and provide your Email IP.
Please do select mail server type as Dedicated and provide error code as you get in Bounce mail.
Microsoft Support will get in touch within 6 hours at most and your mail IP should be mitigated if it Fullfill Step 1 to 3.