isabelpmubago on "[Plugin: CoursePress] PayPal payments"

Hi! I have a problem with the PayPal system. I have my PayPal accunt, my Api user, password and signature (in fact, this account is working perfectly in another web site of my own). But in Coursepress I'm trying to verify it can work but it doesn't. This is the message: 10002 - Security error - Security header is not valid.

Any idea?

Thanks!

https://wordpress.org/plugins/coursepress/