We are running a Filezilla FTP server here.
The problem we are having now is under the setting of the passive mode, the IP address was used to setup as our internal IP address. It worked for some clients(don't know why,don't know how). Apparently it failed on other clients. Then we changed the IP address to our external IP address, and I assumed this should be the correct setting.
But the clients who were able to connect before are now having problem connecting.
They are getting exact error message says"Error: Failed to retrieve directory listing"