Paypal account doesn't change

I got a new paypal account and I changed it in Configuration - Payment Plugins - os_paypal but it does NOT work on the frontend ... there the old address is linked when choosing paypal as payment method (I also have bank transfer and we have two languages if this is important)? What am I missing?

Hi Marco,
You need to open your existing Donation Campaigns and check to see if you already added old Paypal account in the past
Thanks
Dam