Fatal error: ... error setting certificate verify locations

[icicic]

I'm trying to get the PayPal PHP SDK working on my local environment:

PHP 7.4.16

MAMP 6.4

Mac OS Big Sur

I have SSL working with MAMP on one of my local sites

Fatal error: Uncaught PayPal\Exception\PayPalConnectionException: error setting certificate verify locations:
  CAfile: /Applications/MAMP/Library/OpenSSL/cert.pem

Can someone explain how I set up a certificate to work with the PayPal SDK, I don't fully understand certificates and what the Paypal SDK requires?