I can't enter softaculous app installer

[Admin]

I checked that account, and when logging in to FTP, I see the following error:

421 Home directory not available - aborting

So I think you’re also affected by this issue from a few days go:

Infinityfree file management does not log on

In the FTP logs, I see the server responds with “421 Home directory not available - aborting”. This can have one of two reasons: The hosting volume your site is on is not working properly. The folder of your website has been corrupted. I checked a few other accounts on the same hosting volume and they all work, so I think it’s option 2. If this is a new account, I would recommend to deactivate this account and create a new one. You can go to the Addon Domains section of the existing account…