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 Serg Zhitar

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.