Zend certified PHP/Magento developer

Paypal (payflow) returnurl change Magento 2.4

I have 2 websites both using same magento 2.4.2 platform and template. I use Payflow Pro for payment checkout. One appears to be operating correctly. But the other hangs when waiting for Paypal feedback.
The only difference in my Debug log for the payment is the returnurl, errorurl, and cancelurl
The website that displays result of payment (ie ‘payment has been declined notification’) does NOT have the index.php in the 3 response urls. The website that hangs and gives no feedback has the index.php in the urls, like example below.

'returnurl' => 'https://domain.com/index.php/paypal/transparent/redirect/',
'errorurl' => 'https://domain.com/index.php/paypal/transparent/redirect/',
'cancelurl' => 'https://domain.com/index.php/paypal/transparent/redirect/', 

where can i find the code to get rid of the index.php in this url. Then i can see if this is what is causing the issue. Does anyone know if the index.php will make a significant difference in why my cart is hanging?