Hey @amanchella! I’ll try to help you with this!
You can try restoring your project from Autosaves or Backups by going to your project folder and navigating to YourProject/Saved/Backup or YourProject/Saved/Autosave, then look for .uasset files related to your mannequin or animations, copy those files, and place them into your Content folder to replace the broken ones.
Hope this helps!