Switching to mode ‘Offboard’ is currently not possible. Check for a valid position estimate

I used the t265 to provide indoor positioning for the px4 quadcopter drone without gps. The t265 performs well in postion mode. When I tried to start offboard mode on the actual plane.I can’t switch offboard mode manually in qgc. Once I used the remote to unlock the drone and tried to switch the manual mode I was prompted: “Switching to mode ‘Offboard’ is currently not possible. Check for a valid position estimate”
I thank in advance anyone who can help me.

This is how I started t265 and the code:

cd ~/catkin_ws/src/VIO
source ~/catkin_ws/devel/setup.bash
roslaunch px4_realsense_bridge bridge_mavros.launch

The vio code I use comes from:
https://github.com/dbaldwin/VIO
I only changed the udp address in “bridge_mavros.launch” to “udp: // @192.168.1.135:14550”.

but the terminal always show that
“[ INFO] [1690700756.358297606]: HP: requesting home position”
I can’t make sure if this warning trigger the mistake after than.

and I try to start my program
“source ~/catkin_ws/devel/setup.bash
roslaunch px4_realsense_bridge bridge_mavros.launch”
"GitHub - btak9527/offboard_code"this link is my program

than the most confused things is that when I try to start offboard model the qgc shows that
“Switching to mode ‘Offboard’ is currently not possible
Check for a valid position estimate”
but I can switch to position model,

I really can’t solve this problem.I’m very appreciate if you can help me.