Can't export a gif after making it larger than original size

[Ofnuts]

In recent Gimp, you can easily have layers that extend beyond the canvas. The Crop tool in particular now default to not cutting the excess pixels when you crop (the Delete cropped pixels is off by default). To fix your image:

• Start the crop tool
  
• Check Delete cropped pixels
  
• Uncheck Allow growing if set
  
• Make the biggest crop possible (should align to the canvas)
  
• Apply Crop
  

You should then be able to export as GIF.