I confirm the paypal API are correct. You can connect on my

I confirm the paypal API are correct.

Please try and tell me.

Thanks a lot

Hello there Cedric,
Thanks for posting on the forums and being a WPMU DEV member.
Are you using PayPal in sandbox or live mode ?
Whatever mode you are in, kindly ensure that you are using the right PayPal email and the API credentials.
Can you kindly confirm that and let me know if you are able to fix it ?
If not, kindly allow me a closer access on your site so that I can test it with my PayPal credentials and see if that makes a difference.
You can enable support access via :
WordPress Dashboard >> WPMU DEV Dashboard >> Support >> Staff Access >> Grant Access.
If you have not installed WPMU DEV Dashboard plugin yet, kindly do that here : https://premium.wpmudev.org/project/wpmu-dev-dashboard/ and then allow access as per the above process.
Cheers, PC