The error returned from paypal is:
Short Error: Authentication/Authorization Failed
Long Error:You do not have permissions to make this API call
From the way you have masked your the username, it looks like you are using your email address for the api username. the username you need to use is not the same as your email address.
In your paypal account, view the API details, the username to use is the API Username listed on the API details page.
You need to use the API Username, API Password and API Signature from this page.
For express checkout, there are three places you will need to update those details>
1) On the checkout page, update the "Authentication for PayPal Express Checkout" server behavior
2) On the confirm page, update the "Get Payer Profile From PayPal Express Checkout" server behavior
3) On the confirm page, update the "Process Transaction PayPal Express Checkout" server behavior