Public Json Web Key - Bubble.io

Hello,
I have tried to connect my box to bubble.io to upload images. I had some troubles and then tried it again with another account. As I deleted the first account and tried it with another i got following error message.
Now I do not have access to the first account and therefore cannot delete the public key there.
I am not able to generate a new one as a bubble project predefines its json web key.