Hi @atilus, Thank you for contacting PayPal community. We apologize for any inconvenience. I have tried to reproduce the issue and could able to upgrade my sandbox account to Pro successfully without any error. Please find the below snapshot for reference. Can you please try now, you shouldn't be facing any issues. Sincerely, Chiranjeevi PayPal, Inc. If this post or any other was helpful, please enrich the community by giving kudos or accepting it as a solution.
... View more