Error in testing demo (Cart Delivery)

hi,when i runing the demo cart-delivery i got error as follows after press “PLAY”

2020-07-21 11:30:25 [1,110,527ms] [Error] [omni.isaac.dynamic_control.plugin] DcWakeUpArticulation: Invalid or expired articulation handle
2020-07-21 11:30:25 [1,110,527ms] [Error] [omni.isaac.dynamic_control.plugin] DcSetDofVelocityTarget: Invalid or expired dof handle

ENVIRONMENTS:
ubuntu18.04
isaac_sim(docker image:nvcr.io/nvidia/isaac-sim:2020.1_ea)
GPU:RTX 2080Ti
nvidia-docker

Is there anything showing in the viewport, or did it fail to load the models?

it has successfully loaded the models and started the Robot Engine Bridge.and when i use nvidia-docker run the demo,both of isaac_sim and isaac_sdk,there is an error in connecting them on port 55001 and 55000.

i have fix the error by change file /isaac_sim/_build/linux-x86_64/release/exts/omni.isaac.robot_engine_bridge/resources/isaac_engine/json/isaacsim.app.json in docker image and add -p 55000:55000 when runing the isaac_sim image.

there is the content of json file

{
“name”: “isaacsim”,
“modules”: ,
“graph”: {
“nodes”: [
{
“name”: “interface”,
“components”: [
{
“name”: “ledger”,
“type”: “isaac::alice::MessageLedger”
},
{
“name”: “input”,
“type”: “isaac::alice::TcpSubscriber”
},
{
“name”: “output”,
“type”: “isaac::alice::TcpPublisher”
},
{
“name”: “time_sync”,
“type”: “isaac::alice::TimeSynchronizer”
}
]
}
],
“edges”:
},
“config”: {
“interface”: {
“input”: {
“port”: 55001,
“host”: “IP of your isaac_sdk
},
“output”: {
“port”: 55000
}
}
}
}