That’s because most of the time, it’s not a problem with the FTP server, but a client side connection issue. And we have no ability to fix networking issues on the client side.
FTP is a finicky protocol. Most of the time it works, but in some special network cases it doesn’t. Usually, this is caused by network administrators trying to “fix” or “optimize” the FTP connection, which generally ends up breaking it.
The only way we could “fix” this is to provide a suitable alternative to FTP entirely. But we don’t.
Could you please share the logs from FileZilla so we can have a better idea of why it doesn’t work?