Sandbox Error - API call failed

[Jason92s]

Our live site is working great, but our development site stopped processing payments yesterday.  Our config files are exactly the same, with the exception of the API credentials.  The sandbox credentials don't work anymore.  I ported this code over from a PayPal Express Checkout script I found online and it's been working great.  Now, whenever I attempt to checkout, I receive the following message:

SetExpressCheckout API call failed. Detailed Error Message: Short Error Message: Error Code: Error Severity Code:

If I use the live API credentials, everything works great.  Any ideas?  Thanks.

[webtree22]

I am experiencing the same problem. No error/error code is returned. simly "SetExpressCheckout API call failed. Detailed Error Message: Short Error Message: Error Code: Error Severity Code:"

The script (PHP) was provided by the PayPal Demo (http://demo.paypal.com/) as was working excellent till yesterday. Now Nothing? 

What can be the problem?

[webtree22]

I was having the same problem.  I was also using the code they provided PHP in thier express checkout demo site.

I researched the web and found this page: 

https://www.paypal-knowledge.com/infocenter/index?page=content&widgetview=true&id=FAQ1914&viewlocale...

I am using PHP NVP. I then upgraded my php_curl.dll file in my localhost (By upgrading the PHP version - Actually I upgraded the wampserver). 

Now it works well. So it seems issue is not with the code but with the environment where the code is being implemented.

Hope it helps.