NOP 3.8 - payment error: onject reference not set

Hi

I'm testing this on NOP 3.8, with a Paypal sandbox account.  When selecting Paypal checkout, I get this error - Payment error: Object reference not set to an instance of an object.

In the browser Developer console I can see this message:
Error: "Payment error: Object reference not set to an instance of an object.
./node_modules/post-robot/src/index.js/_RECEIVE_MESSAGE_TYPE[conf.b.POST_MESSAGE_TYPE.RESPONSE]@https://www.paypalobjects.com/api/checkout.js:2563:31
receiveMessage@https://www.paypalobjects.com/api/checkout.js:2605:25
messageListener@https://www.paypalobjects.com/api/checkout.js:2626:13
"

and in the Debug file:
2018.09.18 16:51:38:7814*******
PayPalExpressCheckoutPayment. CreatePayment. CurrentCustomer.Id=1, IsCheckout=False, jsonFormData=__RequestVerificationToken=avH8xa5ZSLmZfFQzC5qvHVQbUUg2LfIhc-HIM_Jkp_33msOam3R-it70K0dpzUgfI67Uf4B5HscyfNofk7AglaNi76QpE0NM8oJwE8a_41SMnyB-ofWGG4WMKg99172gnSHno7XnaG49uFfR5019TQ2&itemquantity523=1
2018.09.18 16:51:38:7957*******
PayPalExpressCheckoutPayment. CreatePayment. FormCollection form
    __RequestVerificationToken-avH8xa5ZSLmZfFQzC5qvHVQbUUg2LfIhc-HIM_Jkp_33msOam3R-it70K0dpzUgfI67Uf4B5HscyfNofk7AglaNi76QpE0NM8oJwE8a_41SMnyB-ofWGG4WMKg99172gnSHno7XnaG49uFfR5019TQ2
    itemquantity523-1

2018.09.18 16:51:39:7312*******
PayPalService. CreatePayment. has apiContext
2018.09.18 16:51:39:7381*******
PayPalService. CreatePayment. has order amount
2018.09.18 16:51:39:7550*******
Error. PayPalService. CreatePayment. ErrorMessage=Object reference not set to an instance of an object.

Any idea where I am going wrong?

Thanks

I don't know....
I'll do new release with extra logging information and we'll find the problem.

Download new release from our site.
Replace DLL file and restart your site.
Create the PayPal payment
send this plugin log information.
I need to see such messages

PayPalService. CreatePayment. step ....

I think you have null any of address (shipping or billing) but plugin has to solve this problem.
I wait.

I downloaded again,
replaced the dll files for version 3.8 (even tho the modified time stamps on the files hadn't changed),
restarted the site and got exactly the same result as before.

Also tried clearing browser cache and Nop cache.

Debug:
2018.09.20 11:34:56:8145*******
PayPalService. CreatePayment. has apiContext
2018.09.20 11:34:56:8145*******
PayPalService. CreatePayment. has order amount
2018.09.20 11:34:56:8145*******
Error. PayPalService. CreatePayment. ErrorMessage=Object reference not set to an instance of an object.

Clear the browser cache.
You use the old release of plugin.
Check the new ZIP file if it has a new DLL.
Replace new DLL and restart IIS application pool.
If you need I can connect to your PC using TeamViewer, etc.