Hey @Vaibhav.narwade ,
normally autosave doesn’t work if any of this factors are present: Saving changes to analyses - Amazon QuickSight
If you are sure your are the only one working in that analysis, try @Sanjeeb2022 solution here: Facing Autosave failed error dialog box 100 times during dashboard development
If this also doesn’t work you should open a customer ticket.
BR
Robert