I had the same that it’s not showing any new data since Feb 1st 2024. And checked FAQ here: Unity Analytics FAQs
When will Legacy Analytics be shut down?
Legacy Analytics is no longer available to adopt or access in the dashboard. As of January 31, 2024, the legacy Unity Analytics platform will cease the transmission of new data for analysis to Analytics. The automatic forwarding of data from the legacy Unity Analytics product will come to a halt, and only data generated from the Analytics SDK will be accepted moving forward.
What happens if I don’t transition before the specified date?
If you don’t transition before January 31, 2024, you will no longer see new data in the Analytics dashboard and your analysis will be limited to historical data.
I guess it was Legacy Analytics and it shut down.