You’d have to provide much more information for us to be able to give you any guidance.
Maybe someone here knows what you mean by “block_introduction_to_programming”, but I imagine most won’t. Can you provide more information? A link?
Also, what changed? You say it always worked and now it doesn’t. Are you working in a different place? Are the versions updated? Did the software update?
Where and how? This doesn’t sound like standard Jupyter and so you’d have to share information about this.
If it was using an old extension and you updated to new Jupyter tech where that extension doesn’t work, then this may be the type of behavior you see.
Please read Getting good answers to your questions. Pay particular attention to the admonition ’ DO NOT post images of code, data, error messages, etc’, under the section ‘Help others reproduce the problem’.