Getting an error on console.log when clicking the save button on the PayPal Commerce Platform from the admin side

I have using OC 4
I want to setup PayPal Commerce Platform when clicking the save button getting an error on the console

Warning: Undefined array key "message" in /extension/paypal/admin/controller/payment/paypal.php

Then I went to this file and printed the array and saw that there is no key (message) existing in that array and the save button is not working due to having an error in the console.

Please help me to fixed this issue

You would be best to contact the developer or OpenCart support for that.