Expired Domain for https://ntbk.io/csharp101-notebook01

### Is there an existing issue for this?

- [x] I have searched the existing issues

### URL

https://ntbk.io/csharp101-notebook01

### Browser

Firefox 138.0.3 (aarch64)

### Description

Domain for the notebooks seems to have lapse.

### Additional context

_No response_