Hello @ryanf369fd411f1943c8,
This is due to an outdated instruction in the notebook, it will be updated.
Thanks for sharing the error, we have solved in previous posts, please check here: 404 Not Found nginx/1.14.0 (Ubuntu)
You should be able to access the link as following:
https://i-08966137a7862b2c8.robotigniteacademy.com/your-custom-address/stream?topic=/camera/rgb/image_raw
Please, let me know if that works for you
Regards