Cox.net email addresses not receiving verification emails from Outlook.com

Greetings,

I have a couple of Outlook.com email addresses that I use. In Outlook.com's security settings, I want to set my Cox.net email address to receive any security notifications or codes sent by Outlook to verify my account when I change a security setting in my Outlook accounts. But my Cox email accounts never receive them. In other words, I can't use my Cox email account to verify that I'm the owner of my Outlook.com account.

I've tried my different Cox email addresses and none of them receive verification codes from Outlook. I've checked my Webmail accounts, disabled all Spam filtering, checked Spam and all other folders...and still nothing.

But if I send normal email from my Outlook.com addresses to my Cox.net addresses, those come through and vice versa.

Please advise how to resolve this or have Cox correct this blocking issue, since Outlook.com is a major provider of email services and Cox shouldn't be blocking them, especially security & verification emails.

Thank you.