Please note that you need to have visited your control panel at least once after creating your infinityfree web hosting which will activate your ftp before sitepro will function
This happens occasionally. We’re not quite sure why it happens (it definitely shouldn’t be a firewalling issue), but it is clear that it’s a temporary issue. So if you see this error, please just try again later.
Note that the usual “check your password, check FTP access, etc.” is not relevant. The client area checks whether FTP access is available before opening the builder. So if FTP access was disabled for your account or the password was out of sync, you wouldn’t be able to access the builder to begin with.