I cannot complete Apple Developer Program enrollment. Web enrollment at developer.apple.com/enroll fails at the entity-type step with "We are unable to process your request. An unknown error occurred." I selected Individual / Sole Proprietor. The Apple Developer app says enrollment through the app is not available for this Apple Account and redirects back to the web page. I filed support case 20000119352612 and also requested a callback, but have had no response for over a day. My app is finished and ready to submit. Could an Apple engineer advise what is blocking enrollment on this account, or escalate the case?