If you enter a nether portal just as it breaks, you get sent in a phamtom world where there is nothing, the game reacts to nothing, and it's maybe only me, but it can't save the world, you have to forcefully shut it down. When you relog there will be no problem.
Related issues
duplicates
Attachments
Comments
migrated
[media]
pine1needle
This is a duplicate of MC-175067. You were teleported really far away to chunks that had never been loaded before. Your computer was trying to generate all of those chunks at once, which created a ton of lag. (Your screenshot shows that the integrated server was running at 118 milliseconds per tick.) The extreme lag caused your computer to not respond to your input.