Why do some images fail to import? And what to do about it?

We are now adding products from Aliexpress and have over a hundred imported now. Of those ti says we have 39 failed images. The plugin has finished importing all the background images.

Is there a reason why those select images are not importing and how do I fix them? 1 product has 4 images that did not load bu the others are from many different products. it would be help if it said why they did not import and how to fix it. I have tried to reimport them.