The tag and anchor sometimes cannot read the distance

Hello, I am a beginner in UWB, I need some help, the wiring and code I am currently using are all on the Internet, but I often have problems with the connection, there is no way to read the distance, and I can’t find the problem So, is there any possibility?

“The following is my implementation”
code: Arduino-dw1000-master
tag: Arduino Mega uses a 9V battery for the power supply, dwm1000 uses a 18650+ boost module to make the voltage 5V for the power supply
anchor: Arduino Uno uses a 9V battery for the power supply, dwm1000 uses a 18650+ boost module to make the voltage 5V for the power supply

Sincerely thank you for your help
p.s.If you need any other information, please let me know