This situation has several explanations.
1. You’re entering an incorrect tracking ID.
2. Your order hasn't been entered in the tracking database of the respective service yet.
If you chose standard shipping for your order, the package may have left the Czech Republic, and is now untraceable until the destination country's postal service claims it.
After leaving the country of origin, the parcel travels to a foreign country where it is accepted at customs services. This is where most delays happen. The delivery will appear in the customer's post tracking system only after it has been released by customs.