I don't want to throw anyone under the bus here, but I think the error handling for the D-U-N-S number verification step could be improved.
Shown on page:
The information you entered did not match your D&B profile. Before submitting your information, check your D&B profile. If you've recently changed your legal entity name, update your D&B profile.
This message is confusing when the only information provided is the company name, which exactly matches the D&B profile.
We get more information about the error in console than what is shown on the page:
"resultCode": 20010,
"resultString": "Your organizations information is not complete.",
"userString": "Your organizations information is not complete.",
"requestUrl": "https://developer.apple.com/services-enrollment/validateDunsDetails",
Displaying a clearer error message in line with this would greatly improve user understanding of what went wrong.