I use two servers.
The first one I can access through SFTP - no problems.
The second one I try simple FTP and it does not work. I have used it many times this morning, then it crashed.
I tried also through Filezilla and it gives me the same answer. Other users are able to connect to the Second server without any problem. It tends to indicate it is a local problem, like "block" from the Firewall or something like that. I can http to this server though!