PayPal fails for cash transactions but works for amounts of £0.00

Hi,

I am trying to finalise a shop for a client and have set up payments through Paypal Direct and Paypal Express using the API access and testing through the sandbox.

When attempting to pay for an item using Paypal Direct that has a price of £0.00 it works fine but when I attempt to checkout with an item that has a cash figure say £50.00 then the following error appears in the confirm your order box:

LongMessage: Security header is not valid ShortMessage: Security error ErrorCode: 10002

Also when I attempt to pay using PayPal express I get the following error message:

LongMessage: Security header is not valid
ShortMessage: Security error
ErrorCode: 10002
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: NopSolutions.NopCommerce.Common.NopException:
LongMessage: Security header is not valid
ShortMessage: Security error
ErrorCode: 10002


Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[NopException:
LongMessage: Security header is not valid
ShortMessage: Security error
ErrorCode: 10002
]
   NopSolutions.NopCommerce.Payment.Methods.PayPal.PayPalExpressPaymentProcessor.SetExpressCheckout(Decimal OrderTotal, String ReturnURL, String CancelURL) in D:\Work\Own\NopCommerce\Solution\PublishedSite\Solution\Payment\Nop.Payment.PayPal\PayPalExpressPaymentProcessor.cs:218
   NopSolutions.NopCommerce.Web.Modules.PaypalExpressButton.btnPaypalExpress_Click(Object sender, EventArgs e) in D:\Work\Own\NopCommerce\Solution\PublishedSite\Solution\NopCommerceStore\Modules\PaypalExpressButton.ascx.cs:87
   System.Web.UI.WebControls.ImageButton.OnClick(ImageClickEventArgs e) +108
   System.Web.UI.WebControls.ImageButton.RaisePostBackEvent(String eventArgument) +118
   System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

I have checked my API Access details and they are correct.

Can anyone tell me what the problem is please.

Thanks

I am getting this error message on the confirmation page trying to process credit card manually.:

LongMessage: Security header is not valid ShortMessage: Security error ErrorCode: 10002

The error you are getting can happen if the API credentials and environment don't match up.  The "live" PayPal system and the "sandbox" PayPal System have two different, not-interchangeable API certificates. When using the sandbox endpoint one needs to have the sandbox API certificate, obtained from sandbox.paypal.com and/or developer.paypal.com. When using the real or "live" endpoint one needs to have the real API certificate, obtained from www.paypal.com.

Thanks for that. I knew I was doing something stupid.

Thanks. I had also paypal direct sandbox enabled but with the live credentials.

I had real paypal credentials and was using sandbox. Many thanks .

+2 I did the same thing, thanks for pointing out the sandbox check mark.

Mine is not this case, no sandbox enabled, username, password and signature are from live account, still getting this error, please help, my site is live and losing buisness :(

LongMessage: Security header is not valid ShortMessage: Security error ErrorCode: 10002