These are images originally shot overseas on cellphones, transmitted via Whatsapp. I've successfully imported hundreds of these in the past.
Not all cellphones in regard to the cameras are the same....................LR needs to be able to recognise the files. Though having said that a JPEG file (unless in some way corrupted?) should not be an issue, has the cell phone in question been set to shoot in raw?
Is it possible that Whatsapp has in some way corrupted the files so that they are no longer recognised? Are they viewable on your computer apart from in LR, such as in Windows Explorer?
Do say which cellphone make & model this one is, because this just might have been reported elsewhere. Oh, and which version of LR are you using?
As you can see the devil can be in the details and without the fullest of information folk can only speculate.