iphone does not appear in photos

I'm trying to import photos taken on my iphone 6S into the Photos library on my macbook. Photos 3.0, Mac OS High Sierra. The iphone simply doesn't appear in Photos anymore, and going to file > import only lets me import from the file system, not from devices.

I know the phone is connected fine, I just backed it up and synced it in itunes, so that part is working. The phone is unlocked. Not sure what else I can try; the phone used to just be there.

Thanks for any assistance!