Unstable uplink when I add as923 and use it

I am using stm32- LMIC library v1.6, and there is no as923, and so I reference to this to add as923 frequency for the program. Finally, it works. However, the uplink is unstable that the system shows yello-green thunder and the uplink data immediately sometimes or it will keep retrying yello-green thunder many times and then show the uplink data.

Then how to solve it? Would it be affected by gateway as other devices also use the same gateway or just the programming problem?