Sorry that you cannot import images in Lightroom CC.
Do you rename your photos on import? If so, Lightroom compares the name of the file you're about to import with files already imported, and does not find a match. It does check other metadata too, but when it isn't 100% sure the file is a duplicate, it will error on the side of caution and import the photo. If you want to rename your images, you can either rename them after import to avoid duplication, or you can format your card after each import and continue to rename as part of the import process.
Akash, the problem is that the duplicates detection isn't working correctly in the case of these scanned images, and is actually preventing the images from being imported, even though they are different scans (but with the same filename). This has already been flagged internally, see Can't import image scans as Lightroom thinks is duplicates | Photoshop Family Customer Community
Thanks for the correction. I thought that OP is having issues importing the images that are showing up as duplicates not that the duplicate detection isn't working. Just checked the bug details and it seems like an odd behavior.
I have a similar problem. Even after having renamed the files completely it still says that they are duplicates. How can I still import my photos (#240)? Thanks!
So how do we solve this problem? Even if I change the file name, it won't import images it THINKS are duplicates (they aren't - portrait is smiling in one and not the other, although similar poses)
Lightroom does not look at the content of the images, it only looks at file names and capture dates. The latter may be the problem. Scans do not have a capture date, only a file creation date. You may need to find a utility that can change that. BTW, I have no problems importing scans in Lightroom Classic, so this must be a Lightroom cloud issue.