From Shopify Wiki
PayPal is the safer, easier way to pay and get paid online. The service allows anyone to pay in any way they prefer, including through credit cards, bank accounts, buyer credit or account balances, without sharing financial information.
PayPal has quickly become a global leader in online payment solutions with more than 153 million accounts worldwide. Available in 190 markets and 17 currencies around the world, PayPal enables global ecommerce by making payments possible across different locations, currencies, and languages.
Paypal and Shopify
Because of PayPal's global availability, it is one of the most commonly used gateways on the Shopify platform. About 60% of Shopify merchants use one of PayPal's services. Shopify currently supports the following PayPal payment services:
- PayPal Express Checkout
- PayPal Website Payments Pro (US)
- PayPal Website Payments Pro (CA)
- PayPal Website Payments Pro (UK)
- PayPal Payflow Pro (Verisign)
The Shopify team highly recommends Website Payments Pro (WPP) where available, as it integrates into Shopify better because the underlying technology is a lot more robust.
WPP also leads to a better customer experience because customers are not redirected to PayPal pages during the checkout which reduces the amount of conceptually and visually different steps. Customers can enter credit card details directly on Shopify's checkout pages which is a more natural process for buyers.
Payflow used to be part of the Verisign payment systems and was aquired by PayPal in 2007. You can read more about the acquisition at http://www.verisign.com/support/advisories/page_PAYPALFAQ.html .
Payment has already been made for this InvoiceID
Chances are you've used the same PayPal account before, or are using it with another shop, thus the order ID has already been used.
What you need to do is edit your order ID format. You can find out how to do that in the following article: How can I change my Order ID's?
My paypal orders don't show up
PayPal sometimes experiences delays in their IPN (Instant Payment Notification) service which is the mechanism used to tell Shopify about completed orders. This seems to be a common issue in Australia. Delays can range from a few minutes to several hours. IPNs are only part of the Website Payments Standard package. Website Payments Pro does not have this issue and all orders should show up immediately.
Invalid Vendor Account
If you are setting up PayPal and you get the message "Invalid Vendor Account" this is probably because you failed input all the necessary credentials.
First generate "Payflow" credentials in your PayPal account and enter those in the boxes for PayPal in Shopify. The Vendor, User, and Password are all required for certain account types.
This transaction cannot be processed due to an invalid merchant configuration.
Please complete the following checklist:
- Make sure you've signed up with PayPal for PayPal Website Payments Pro. This is a services provided on top of the standard PayPal package and costs approximately 30$ USD a month.
- Have agreed to the billing agreement of PayPal Website Payments Pro?
- Have the correct PayPal email address entered in Shopify?
- Have given our PayPal API account the appropriate API permissions, as described on the payment preferences page?
Third-party authentication: Grant Shopify the appropriate API authentication permissions
1. Log in to your PayPal account and click the Profile subtab. 2. Click the API Access link in the Account Information column. 3. Click the Grant API Permission link. 4. In the Enter an API Partner Username field, enter scott_api1.jadedpixel.com. 5. Check the following API permissions: * Express_Checkout * Direct_Payment * Admin_API * Auth_Settle 6. Click the Save button.
The particular error you've received is mentioned here:
If you are not signed up for PayPal Website Payments Pro then you can use PayPal Website Payments Standard, which is under "Accept External Payment Service" in the Checkout & Payment screen of Shopify.
Error from gateway: Too many requests for operation
This error occurs when too many request have been sent to PayPal too quickly. PayPal mistakes this for a type of Spam attack. You will have to wait a few hours and try again later, or contact PayPal and have them reset the account.
You can test the Credit Card processing capability by creating a test product for several dollars and purchasing this from your own store. PayPal has a minimum amount restriction, so your test product will need to be $2 and up.