I think they blocked me.  I am pretty sure everything was fine until I called them.  They said I am not allowed to have NOPcommerce even though it is in my downloadable apps.  I took there banner off and then put it back on but they took it back off and now I have this problem.  I am definately moving and taking some clients with me.


Server Error in '/' Application.

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 PayPalExpressPaymentProcessor.cs:217
   NopSolutions.NopCommerce.Web.Modules.PaypalExpressButton.btnPaypalExpress_Click(Object sender, EventArgs e) in PaypalExpressButton.ascx.cs:91
   System.Web.UI.ImageClickEventHandler.Invoke(Object sender, ImageClickEventArgs e) +0
   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


Version Information: Microsoft .NET Framework Version:2.0.50727.4200; ASP.NET Version:2.0.50727.4016

Any resolution to this?  I'm using GoDaddy as well...

im not sure what you are doing but i have godaddy as well and all you have to do is set it up from the app section or just download it from here. they cant tell you what kind of website you can have!!
if you need help i can try to set up for you.

Thank you very much for your offer to help!  After posting this, I discovered that the Use sandbox checkbox was checked in the configuration and I was trying to use a real paypal account with it.  I changed my paypal account info to a sandbox paypal account and it worked after that.  I guess after testing and making sure it all works and I switch to use a real paypal account, I'll uncheck that sandbox checkbox and hopefully it will still work.