Answer
Hashchats keeps confirming with Stripe for a few minutes after the loading indicator closes and shows a success message once your plan is active. You see an error right away only if Stripe reports that checkout was not completed. If confirmation still has not arrived after those checks, a message asks you to refresh Account Management. If the page still shows your old plan, refresh the web app, wait a moment for Stripe confirmation to finish, and check Account Management again. If your Pro plan still does not appear, contact support with your Hashchats account email and the approximate checkout time so we can help investigate. Do not send passwords, verification codes, or full card numbers in support messages.