Ftp problems

Hello everybody
A few weeks ago I created a second profile as a non-exclusive author.
The fact is that I am trying to upload a package of more than 400 megabytes by ftp and I get an error all the time.
I have created my own key. I enter it together with my user “Relaxyou” (port 21) and the hostftp.author.envato.com and I cannot establish a connection.
I have also tried to do it with ft.marketplace.envato.com and nothing.
Would someone be so kind as to explain to me what may be failing?
I would appreciate any help.
Thank you

Can somebody help me?
I have tried new keys and none seem to work.
What are the correct steps, please?