Photos did not transfer on back up

I transferred all of my data from my iPhone 7 to my new iPhone 12 Pro and everything went well except a bunch of older photos are blacked out and gives an error when they are selected. The error says “unable to load photo. An error occurred while loading a higher quality version of this photo.” The photo is still viewable on my iCloud account and my older iPhone.

how do I fix this so that all my photos display properly.