Half my photos/videos won't import from iPhone
All of a sudden 2 of my families iPhones (one is an iPhone 7 and the other an iPhone X) are having serious trouble transferring photos/videos into Photos App. I have these phone for years and once every 2-3 months I transfer the photos/videos into my Photos library on my computer (actually I do it to 2 computers so I always have a backup). Last time I did it successfully was November 1st. On January 1st I planned to transfer all remaining 2019 photos/videos so that I could close out my 2019 library (I keep separate libraries for each year). Unfortunately I kept getting error 9937. I tried 2 other Mac computers I have in the house and same problem. Its not consistent, in that sometimes I will try to import and certain files won't transfer, but if I try again (sometimes on the same computer after re-booting, sometimes on one of the other computers) it works.
This is clearly a new problem but I cannot find any info online that indicates what apple did that caused this.
Please help
iPhone X