I have a vsftpd server sitting in my DMZ which we have been able to connect to from the outside for a while now. For some reason today the server logs me in but then when it goes to do a directory listing it I receive the error message "Failed to retrieve directory listing"

At first I thought maybe a permissions issue is the problem but I am able to connect to the server and get a directory listing with the same accounts from within my network. Wondering what could be happening?

Thank you.