The main reason why the trip code is not displayed may be signal cross coverage. With the development of network technology, many operators will build many signal towers in two adjacent cities to achieve the effect of signal cross-coverage, which also means that people's mobile phones may be connected to signal towers in another area.

In addition, there is another point that may affect the travel itinerary code display where you have never been, that is, there is something wrong with the system. Generally, this kind of problem rarely occurs. If so, there will be problems with the country's big data.