Topic : Can connect to AFP just fine, but not FTP with same login info

So, I have a client in our network who is running into an issue (which just cropped up out of nowhere, as it has always worked fine before).

Basically, he can access AFP (Apple+K, then server address, username and password) just fine, but when using the same method to access FTP (as in: instead of afp://server.mydomain.com, we’ll use ftp://server.mydomain.com; which works just fine for me and others) he gets a message saying that either the username or password is incorrect when it is exactly the same info used to access the AFP.

A few points:
-He is listed under FTP and AFP as having access to these services in server admin.
-His un/pw combination works just fine for everything else
-Everyone else seems to be able to connect to FTP via this method with their credentials just fine, so obviously methinks there is an issue with his account.
-Perhaps related, but definitely of note: his client machine won’t make a Kerberos ticket for him, saying he is not found in the Kerberos database.

There’s GOT to be a connection here, the question is: what is it? And of course, what can I do to troubleshoot this?

Update:
Turns out (obviously) that for some reason he wasn’t in the Kerb database.
I used the terminal to add him back and successfully get him a ticket on his machine.

Still no FTP access though, even after that.
It doesn’t appear to be an issue with the FTP service itself, as I can login and access it on my client machine just fine with my own credentials, but I can’t get it to work using this other person’s login info (even though it works fine for other services: mail, calendaring, afp, etc).

Thoughts?
😳