Screenshots alone are frowned upon. Please describe things with details in text.
For example, here we’d need to know how you were using Jupyter? On your machine? Or remote? Was the connection/session still active? The kernel looks to me to not be responding and so you may not be connected?
Is this a new set up and have never allowed saving? Or was this only this time?
Remember that normally Jupyter saves checkpoints. Did those work?
One rationale for screenshots alone not being permitted is because isn’t indexable/searchable by the systems used to organize how to find answers for you and others. Please read Getting good answers to your questions. I’d refer you especially under the section ‘Help others reproduce the problem’, in the linked to How do I ask a good question? at the bottom there where it emphasizes in bold DO NOT post images of code, data, error messages, etc.