Misspelled Column Title for “Auther”

when a client goes to manage their uploads, the see a misspelling in the column headers. It should be “Author” not “Auther”. Can you advise how we can change this?
A link to the screenshot: https://www.dropbox.com/s/54xutfff5eh5m3e/Screen%20Shot%202019-05-21%20at%209.55.34%20AM.png?dl=0

The page I need help with: [log in to see the link]