I'm trying to follow these instructions. I log in to developer.paypal.com, then to www.sandbox.paypal.com with a Business account from developer.paypal.com's Sandbox Test Accounts page. Go to Merchant Services, click "My saved buttons". Domain changes to www.paypal.com (is it as it should be?). I choose Buy Now button, specify item name and price, and click Create Button. Remove code protection, copy the code, paste it to a site. Open the page, click Buy Now button, which gets me to www.paypal.com, specify Personal account's credentials from developer.paypal.com's Sandbox Test Accounts page. Click Log In, but it says:
Please check your email address and password and try again
Please make sure you have entered your email address correctly.
Please re-enter your PayPal password.
And yep, I checked if I can log in with those credentials to www.sandbox.paypal.com. What am I doing wrong?
Most likely, it's because I have account of a country where I can't accept payments. As such, I can't put even a test button on a site.
UPD I checked again, and it now works. I see two possibilities here: 1) temporary paypal glitch, 2) I created the button under personal account.