Quick summary

Imagen couldn't prepare your RAW files for upload.

How to fix this

1. Make sure Adobe DNG Converter is installed. If your camera is new, update DNG Converter to the latest version. Adobe adds support for new cameras regularly.
2. Create Smart Previews in Lightroom Classic. Select all photos, and go to Library › Previews › Build Smart Previews. See this Adobe guide.
3. If problems continue, clean install your Adobe apps. See this Adobe guide.
4. Open the photos in Lightroom Classic. If Lightroom Classic can't open them either, the files may be damaged.
5. Try a different RAW format, or convert the photos to DNG with Adobe DNG Converter first, and upload the DNG files.
6. Mac: If this started after a macOS update, go to Apple menu › System Settings › Privacy & Security › Files and Folders, and make sure Adobe DNG Converter has access.