Hi Emma
Thanks for confirmation.
I got some clue now - about whats going wrong for me..............
When I used to submit for payment, address bar of browser displays one PayPal error code at the end of URL.........
checkout/genericError?code=UEFZRVJfQ0FOTk9UX1BBWQ%3D%3D
I searched through this error code in google.
Then I found below forum link where all people facing similar error from pay pal for various applications they hosted in which currency was not Indian Rs - INR and all of them were having PayPal account in India and all of them trying to get money form their Indian cusotmers only but in USD.
https://github.com/braintree/braintree-android-drop-in/issues/53
This forum implies that there is regulation or restriction in India..........that PayPal can not receive or process any payment from Indian Customers in any other currency other than INR.
This is the reason............PayPal could process your payment in USD since you were not form India.
But it ultimately rejected my all payments because I was form India.
Even though PayPal has official started with Indian currencies from 1st March 2018 this year, they still seems to be bounded by this regulation act.
So there seems to be no way if i had account of PayPal in India..............I will not be able to accept payment form Indian Customers.
Unless Moodle provides INR currency in PayPal configuration screen.
There is option that I should Create specific payment button in PayPal to accept Indian payment and include the same in my Moodle's course page. This will resolve my problem of getting payment from Indian customers..............but then it will not register user to course.
in fact there is option in configuring this button to specify INP URL which I can do ............but then I need to know the Specific attribute variables that need to pass to that URL.
Does anyone has idea - which Attribute variables get passed through PayPal IPN notification in normal case..........so that same i can try to configure in my custom PayPal button.
Shriram