Outlook cannot receive emails

Hello,

I currently work for a company that is having difficulty sending to Outlook.com accounts.  I have checked our IP stats and we appear to be in good standing, I have also recently signed up for the SNDS and Junk Mail Program with Outlook.com in order to ensure we do not have any issues with delivering email to your organization.

With that being said we recently been having a problem where sometimes we cannot get our message through to the outlook.com servers.  Everything shows fine on our end and says delivered, however it doesn't seem to come through to the actual mailbox in outlook unless I mark as a safe sender.

Can someone please help me with this and help us understand why our emails are getting delivered, but not showing up in the Outlook inbox.  The Microsoft SNDS status shows our email reputation is at Normal and is not blacklisted.

Thanks