Two MSFT Business Accounts

Question

I have two business that each have their own URL/domain. I have been using one for a long time. This is an E3 based business account...nine licenses.

For a new business I added two Standard Business licenses. I obtained the URL from Godaddy. I followed the processes to create this new set of licenses with the synch process to GoDaddy DNS function. I then created proper email addresses for me and the other team member.

But I get the following message from Outlook when I try send email test message to the new Standard Business account using a unique URL.

"Your message wasn't delivered. Despite repeated attempts to deliver your message, the recipient's email system refused to accept a connection from your email system.
Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that it appears that their email system is refusing connections from your email server. Give them the error details shown below. It's likely that the recipient's email admin is the only one who can fix this problem.
For Email Admins
No connection could be made because the target computer actively refused it. This usually results from trying to connect to a service that is inactive on the remote host - that is, one with no server application running. For more information and tips to fix this issue see this article: https://go.microsoft.com/fwlink/?LinkId=389361"

Question: What is going on?