Answer by vandsh for How to resolve FTP Error “Failed to retrieve directory listing” for Administrator account in IIS 7.5

Ran into the same exact issue and after setting up FTP Firewall Support in IIS to match my external IP, still had the issue. As a last step, I went to edit the actual FTP rule in the Windows Firewall and allowed Edge traversal -> Allow Edge Traversal under the Advanced tab hit Apply/OK and restarted the FTPSVC in the Services. After that I no longer had any issues.