Hello Sir/Ma'am, I want to update my MacBook Pro purchase date for Apple Coverage, can you please help me with this?

The problem I am getting is whenever I try to update purchase date, it shows me error as 'We’re unable to validate your product’s purchase date.' and 'We’re sorry, but we are unable to complete your request at this time. Please try again later.' I tried this many a times even with cleared cookies and cache as well.