Unable to create Codespace

Hi,
I am learning gem5 and wanted to access the codespace for practice, but I am unable to create one. I am getting the following error. Could you please help me understand how to resolve this issue?
<img width="1763" height="946" alt="Image" src="https://github.com/user-attachments/assets/2904ed77-6afc-4fa0-a135-83180f6c0762" />