Isaac SDK: Using ros_bridge to talk to ROS on a different machine

I am trying to get the Isaac SDK navigation application to work with a robot running ROS on a different PC. Ideally, this other PC would be the ROS Master because it’s running the drivers. I tried setting:

export ROS_IP=10.96.4.17

export ROS_MASTER_URI=http://10.96.4.17:11311

before doing a bazel run on the application, but I am still getting the error:

2022-06-22 16:06:23.466 ERROR packages/ros_bridge/components/RosNode.cpp@52: ROS is not running. Please start roscore.

Is there some way of running ros_bridge but having roscore running on the other machine?