It appears that many Starka FTP account settings got messed up. In cPanel, delete and manually recreate your FTP accounts and your FTP should start working again.
Hello I have had the exact same issues as you. For FTP, in cPanel, delete then remake you FTP accounts. This fixed things for me.
For the subdomain (for an add-on domain right?) I was told to send a ticket.
I'm not sure if the problem has yet to be fixed, but since the maintenance, my subdomains are no longer working (other things have been broken too like the add-on domain pointing to domain instead of domain.ca, or having to remake FTP accounts for them to work; but these I managed to fix on my...
I had this problem too.
In cPanel, I deleted then remade my ftp accounts and now ftp is working again, both the Special FTP Accounts, and my newly made ones.