PayPal walked me through setting up Sandbox API credentials today, and when I try to support a fundraiser with $600 in a test transaction I get this error:
Your pledge of $0 is almost complete.
There was an unknown problem processing your payment.
There was a problem connecting with the paypal gateway. (CODE)580022 Invalid request parameter: maxAmountPerPayment must be greater than zero
Prior to calling PayPal back for help, I temporarily removed all custom CSS from the entire site, disabled all other plugins, and restored the Fundraising Plugin to bone-stock.
PayPal merchant services doesn't show any attempted transactions, and says that likely my site is not sending all the required preapproval fields in accordance with https://www.x.com/developers/paypal/documentation-tools/api/preapproval-api-operation.
The fundraiser I am testing with is configured as Crowdfunding with a $3600 Goal, $600 Rewards, and set to checkout directly from the panel (have also tried the elaborate checkout page with same results).
My Fundraising Plugin settings themselves are:
Show decimal in prices: off
Simple donations: off
Advanced crowdfunding: on
PayPal mode: Sandbox
PayPal email address: populated
API Username, password, signature: populated
Application ID: APP-80W284485P519543T (PayPal Sandbox. Have also tried while this field was empty with same results.)
I have tried with per-user checkout types both enabled and disabled, with same results, but prefer it enabled.
Yikes -- please, help. Today is my first day trying to play nice with PayPal and I'm sure some of you may identify the problem readily.