Paypal Testing errors

I get non-stop errors with Paypal Developer. when I try to test Membership Pro using Test Site I get:
We are sorry, we are experiencing temporary difficulties. Please try again later. If this error occurred while making a payment, avoid duplicate payments by checking your Account Overview before resending a payment.

For some browsers, this problem can be resolved by clearing or deleting cookies.
Message 3005...

Does anyone have experience with this and does it have anything to do with the plugin?

It has nothing to do with the plugin itself. Sometime, PayPal sandbox is not reliable but I rarely gets the issue like that. Maybe there was a problem with your sandbox PayPal account ?

If you want, you can try to test it using my Sandbox PayPal account. My sandbox PayPal account is:

Buyer: tuanpn_1357997442_per@joomdonation.com/357997339

Seller: tuanpn_1357997546_biz@joomdonation.com/357997507

Regards,

Tuan