Hi Eowyn
My name is Andre Da Costa; an Independent Consultant, Windows Insider MVP and Windows & Devices for IT MVP. I'm here to help you with your problem.
Can you connect it to another working computer to see if it works or not?
I would also try formatting it through Disk Part, see steps:
Use ExFAT as the file system.
https://www.groovypost.com/howto/format-local-d...
Information in the above link is sourced from a trusted Microsoft MVP blog.