Authentication failed

Authentication failed.
Connection failed.
Non-anonymous sessions must use encryption.

So it looks like you are required to enable encryption for your session:
https://winscp.net/eng/docs/ui_login#encryption

So far...I have been working without problems

MassIVE FTP Server
When setting up your FTP server connection, be sure to use plain FTP with no encryption. Then enter massive.ucsd.edu as the server or “host” name (port 21), followed by your MassIVE username and password, and the client should connect you to your user file space.

Well, the "Non-anonymous sessions must use encryption" message comes from the server.
So something must have changed on the server.
If you want us to investigate further, please post session log file. But you will more likely resolve your problem, if you contact your server administrator instead.

Thanks,

I've just finished to contact with them ...

In the last hours, they change the protocol...

Now it says:

When setting up your FTP server connection, be sure to use FTP with TLS/SSL explicit encryption. Then enter massive-ftp.ucsd.edu as the server or “host” name (port 21), followed by your MassIVE username and password, and the client should connect you to your user file space.

But it doesn't work in this way

Thanks for your attention

Please post a log file for "it doesn't work in this way".

Thanks,
You can find it in attachment

Looks like a firewall problem. Please talk to your network administrator. Or are you able to connect with any other FTP client?