How to solve the delevery email problem to Outlook?

Hello friends!!

I'm running Employment website where I'm facing Outlook mail confirmation problems.

When someone registers on my site from the Outlook account, the confirmation email from my site will not be sent to the users' Outlook account. I want to know why it's not just sent to the Outlook account. sample Error 550 SC-001

Please tell me, does anyone solve this problem?