Setting up a secondary FTP account for GoDaddy CPanel hosting requires different configuration than I expected. The trick is that while the primary FTP account uses SFTP, the secondary accounts need to be configured for FTP over TLS. This was a large enough headache for me that I share the details here so some others may be able to avoid the same issue.
In my case, the primary SFTP account was already in place; the panel below is the GoDaddy Gateway page for creating and managing FTP Accounts. Enter an account name, password and click "Create FTP Account".
When setting up the alternate FTP account in FileZilla, set the protocol to FTP and the Encryption to "require Explicit FTP over TLS".
Notice that the above FTP configuration for an alternate account is different than the FTP configuration for the primary account. Primary account is shown below for comparison, the difference is that the Protocol is "SFTP - SSH File Transfer Protocol".
Time to connect
Back to the secondary account. Click on "Connect" in FileZilla.
Click OK, activity starts.
Good news! Is is connecting via TLS. In the first hit to the site, the TLS certificate for the GoDaddy FTP site will be downloaded into FileZilla and retained for comparison on future connections. Notice that while my GoDaddy domain does not have TLS support installed, the GoDaddy FTP site does. This creates a certificate warning on first connect which in my case, no choice but to accept. To be cleaner, should probably add a TLS certificate to my site. Another day.
When got done, it actually makes sense. Only the primary account is permitted SSH access, so it is the only account which can do FTP over SSH. The secondary FTP accounts have to use FTP transferred over TLS. Set up FileZilla that way, and all works as expected.
(Originally published Feb 6 2016)