SMTP Mail Delivery System error. Help please

Hello everyone,

I’m trying to send emails from my email adress and I have Mail Delivery System error:

SMTP error from remote mail server after MAIL FROM: SIZE=12062:
550 SC-001 (BAY004-MC6F16) Unfortunately, messages from 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

What should I do?
Thank you,

The reason for the delivery failure is provided in the link.

Error code 550 SC-001 : Mail rejected by for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.

Your mailserver IP is in the hotmail blocklist.

Are you using a Shared IP ?

I dont know what IP I have. With whom should I check it: my domain provider or my internet provider?

Try Googling whats my ip. There are plenty of online services to tell you your IP address.

I did not ask how to find out my IP. I asked with whom should I check it to have it whitelisted: my domain provider or my internet provider?

AFAIK it’s not possible to get your IP address whitelisted.

as far as I know it’s possible. but as I see people here dont know how to do it and how to help me.

Well, since it’s that is rejecting your email, that would probably be the place to start.

not, it’s not only outlook, I have the same error with other adresses like hotmail, gmail as well.
Any idea where to start?


You should check your outbound IP address for listed in the various spam block lists.
Since that you can face problems with mail delivery to many mail domains.
You also may want to implement at least SPF records at your domain DNS config, and consider configuring DKIM in the future.

Take a look here for few examples.

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