why XavierB has no signal hdmi

but xavier a allways has output

Dear fixed-term.Zhenfeng.LIU,

Could you please provide more detail information?

  1. Did you flash DriveAGX with NVIDIA SDK manger(https://developer.nvidia.com/drive/downloads)? If yes, please let me know SW version : NVIDIA DRIVE™ Software 9.0?
  2. Can you access Xavier B via minicom terminal? (https://docs.nvidia.com/drive/active/

i have solved the problem .it has recovered by itself. when i tried use mnicom to login the xavier b yesterday ,it failed ,but when i try today ,it shows success. i cant understand what has caused this situation.