Hi Kevin,
What's your issue? Could you give us more details?
Where did you sign in your FTP account? Did you want to access one website or anything else?
This article is as a reference for you :
WebDAV <webdav>
https://www.iis.net/configreference/system.webserver/webdav
More about this issue, it's recommend you ask in IIS forum for more professional help.
https://forums.iis.net/
The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.