JetBot tutorial hangs indefinitely at Starting the simulation... despite pre-downloaded assets

[xihuanafeng]

​Environment​
Isaac Sim version: 4.5
Isaac Lab version: 2.1.0

Reproduction steps:
Create clean environment via ./isaaclab.sh --new
Successfully run template task: python scripts/skrl/train.py --task=Template-Isaac-Lab-Tutorial-Direct-v0
Attempt JetBot tutorial → hangs at simulation start,it will stop in "[INFO]: Starting the simulation. This may take a few seconds. Please wait..."
​Observed Behavior​

✅ ​Template task works​
❌ ​JetBot task freezes​ at:
[INFO]: Starting the simulation. This may take a few seconds. Please wait...
No error messages, progress, or CPU/GPU activity observed after this point
​Troubleshooting Attempted​

Pre-downloaded all required assets locally → ​rules out network issues​
Confirmed identical environment runs other Isaac Lab tasks successfully
​Key Questions​

OS: [e.g., Ubuntu 22.04 LTS]
GPU Driver: [e.g., NVIDIA 535.129.03]

[jasonliuzh]

problem:
you do not have assets locally
the way to solve:
download the asset and load them locally
or
make the wifi can access to amazoncloud