Why does my tracking page say ‘not found’, ‘info received’, ‘waiting for shipment’?

Why does my tracking page say ‘not found’, ‘info received’, ‘waiting for shipment’?
March 27, 2020 zitaruksergij@gmail.com

There can be a delay of up to 48 hours in USPS’s online tracking system.

A tracking number that is “not found” means USPS does not have the tracking number in its system yet or the USPS system is down, which happens frequently.

A tracking status of “info received” or “waiting for shipment” means the shipping label has been paid but the package has not yet been scanned in by the post office.