can't transfer or copy videos from phone to pc

i cant copy vedio files from my iphone 8 to windows 10 laptop, when every i connect it lets few like two files to be copied then it prompt that the device attached not functing. i have done all i know and changed the cable, now new one, i can copy photos but no videos, i can open the phone folder and can copy those files but when i try to open it says file type HEIC is missing. i can even backup and do all but can't transfer videos.