Needs to provide the currency code explicitly in the -bash.00 verification call, otherwise the payment would fail when store's default currency is not USD.

Author: niravkrish

app/code/Magento/Paypal/Model/Payflow/Service/Request/SecureToken.php

@@ -64,6 +64,7 @@ public function requestToken(Quote $quote)
         $request->setTrxtype(Payflowpro::TRXTYPE_AUTH_ONLY);
         $request->setVerbosity('HIGH');
         $request->setAmt(0);
+        $request->setCurrency($quote->getBaseCurrencyCode());
         $request->setCreatesecuretoken('Y');
         $request->setSecuretokenid($this->mathRandom->getUniqueHash());
         $request->setReturnurl($this->url->getUrl('paypal/transparent/response'));