Can you please send an email to Developer@visa.com and let them know you're using Visa Checkout and would like to promote your project into production? From there, someone will work with you to help you get started with the Project Promotion process, such as having you answer a brief questionnaire that you'll submit back to the developer support team. After you submit the questionnaire to them just give it some time for them to review and process your request. Someone will reach out to you soon after that. Hope that helps!
Can you please let me know which country and language you are selecting then receiving the error?