The good news is that this is a very common issue and easy to resolve. Simply navigate to the following form: https://support.dnb.com/?CUST=APPLEDEV
Enter your email address
Enter your contact information (you can use your organization's address)
Select “Developer Program”
Select “Error Message”
Fill out the organization's information on that form (you can disregard Request ID)
Upload at least two accepted legal documents for your organization
For description, copy and paste the following text:
“I am trying to enroll in the Apple Developer program however when I enter my Legal Entity Name and DUNS number, I am receiving an error that my organization could not be verified as a legal entity. I have confirmed that my DUNS number and Legal Entity Name are both entered correctly. Please advise”.
From here, D&B will reach out in a few days to resolve this issue and provide a timeframe as to when you can continue your Apple Developer account enrollment