Magento 1.9 - PayPal gateway has rejected request error

[Aveeva]

Mail remainder,

Payment transaction failed. Reason PayPal gateway has rejected request. 
A successful transaction has already been 
completed for this token (#10415: Transaction refused because of an invalid argument. 
See additional error messages for details).

Checkout Type onepage

Customer: Abc (abc@gmail.com)

Items abc x 1 USD 11 xyz x 1 USD 10 Total: USD 33.93

What is the main cause for this above error?

[Rahul Gupta]

@Aveeva check the below link once.

https://magento.stackexchange.com/questions/190686/paypal-gateway-has-rejected-request-the-transacti...

Thanks

[Rakesh Jesadiya]

It's related to your API Credential issue of Paypal. Verify your Credentials you have added in Paypal configuration value.

Check More details to get Paypal API and Cause of Error,Paypal Gateway has rejected Magento. 

[theMageComp]

Hello @Aveeva 

1. disable HHVM cache on my server

2. Any third party extension you recently installed?

3. Is there any chance of different invoice numbers in current Magento and paypal gateway may have the invoice number already generated before? 
see more idea about it here https://magento.stackexchange.com/questions/85910/paypal-gateway-has-rejected-payment-request

https://magento.stackexchange.com/questions/190686/paypal-gateway-has-rejected-request-the-transacti...

4. Try configuring the PayPal again.