Tracking of past delayed flight

Hi,
I’m looking for a tracking of a delayed flight which occurred the 21st of August 2017 from Porto to Copenhagen. I’m just looking for a document that certifies the flight was delayed.

Thanks

Look up the flight number and click on “View more flight history” to see the last couple months of flights.

Which airline, flight number?
I can look it up for you and give you a direct link.
I am only seeing Ryanair FR8898. And it has arrived earlier on the 21 of August.
https://flightaware.com/live/flight/RYR8898/history/20170821/1535Z/LPPR/EKCH