External Disk Authorization Issues

https://preview.redd.it/658s9xwi86jh1.png?width=251&format=png&auto=webp&s=bddbb34a655875d852acca4c2c91d70323183a35

For some reason recently my external harddrive has been giving me issues with not being able to copy stuff to them or deleting off it it will begin copying but after awhile it will stop and then say I don't have access to the drive shown by a lock next to my harddrive and the same happens with deleting big files how do I fix this?