Thank you for posting the log. Have you deleted files or moved folders around? Try to remove redirectors and run a map check under Build menu. Also, check if your naming conventions for your levels are causing the issue. Can you use Save Current Level as and pick a simpler name without underscores?
I’ll see if I can find something helpful and let you know
Fixing the “Failed to Save” Error in Unreal Engine - YouTube
Failed to save! Unreal engine 4 error solving - YouTube
