Flight departure data is empty

Hi, I have been opensky network API for a few weeks to get flight departures information for multiple US airports on a daily basis. My code is scheduled to run on AWS Lambda every day, and I recently observed that I have been getting empty list for flight departures of all airports since November 6th, 2023. 
The last API call that has fetched me information is (have used just one airport to demonstrate the example, but the dates worked for all airports)
&begin=1699142400&end=1699228800
where the begin date is November 5th 2023 00:00:00 GMT+0000 to November 6th 2023 00:00:00 GMT+0000

I also get a 404 not found when there is empty data fetched from API. Could you please share some insights on what could be going wrong? Is the API for flight departures down? Is anyone else also facing this issue?

Thanks.