PayPal & BrainTree official module not saving configuration on activation

[createit]

I have a site with Prestashop 1.7.4.3 using this module, and on attempting to activate the module, using the second option, which includes accepting credit cards and debit cards, login to Paypal proceeds apparently as it should, however after activation is complete, no data is stored in the configuration table in the Prestashop database.

Over in this thread: https://www.prestashop.com/forums/topic/898692-paypal-braintree-official-module-isnt-working-on-prestashop-1742/?tab=comments#comment-3023179

There is a suggestion to enter merchant id, username, password and signature directly in the mySQL database, which I can do, however Paypal offers several different APIs and I need to know specifically which one to use so I can find the correct values to enter in the database.

At this stage, the values I've tried result in the module saying that it is configured, but result in an error message

'You do not have permissions to make this API call' when attempting to do a test transaction.

The site is in NZ and uses NZ dollars, in case that makes any difference.