Winning notification/invoice does not come through on Ultimate auction pro

I have recently upgraded from free version to Ultimate auction pro but winning notification/invoice does not come.
As you recommended, I have checked my Paypal API and application ID details but they are all OK. Other API functions such as levying listing fee are currently working just fine. Bid notification works well but winning notifications and invoices don’t come. Like I stated previously if I return to free Auction version, it works. What should I do? Thank you very much.

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