The most probable reason for getting this error:
Impossible to connect to the server
when trying to log in to an FTP account is a missing home folder for the FTP account.
The solution is very simple - you have to recreate the home folder for the FTP account. Then you should be able to log in without any problems.
FTP is easy to set up and work with when you have the right host to support you. Check out what SiteGround’s FTP hosting offers and sign up for our services so you could rely on expert FTP assistance!