no connection between gazebo and mavros in rqt graph

[sagardalai]

Hello everyone,

i launch roslaunch px4 mavros_posix_sitl.launch
it launched perfectly.

and after that I try this rosrun mavros mavsafety arm
And getting error
Request failed. Check mavros logs

and there is no connection between gazebo and mavros in rqt graph and indicating there is no connection between px4 and vehicle.

Please help me out if anyone have solution for this.