Magento – Magento 2:Imported resource (image) could not be downloaded from external resource due to timeout or access permissions

I had similar sounding problem with importing product images. In my case the problem was large image files, say 2+MB. I used Photoshop -> Scripts -> Image Processor to batch reduce the images target size/quality for product full zoom.

Providing the exact error message may help get a better answer. Checking Magento logs, PHP logs, and web server logs may also surface the cause.

The error is saying that the image file referenced in row 5 (it says row 4, but that is the last successful imported row before the error) is missing or the spelling is incorrect. The import process cannot find the image at that location. If you remove the image name referenced in row 5, save, and then rerun the import, you should see several more rows imported until the next missing named file.