SFTP on Serv-U/CentOS

Hello,

I'm having some issues setting up users to connect to Serv-U via SFTP. Any help would be greatly appreciated.

What I've done so far:

1. Created a Serv-U Domain
2. Set the following limits...
   1. require secure connection before login: yes
   2. ssh auth type: pubkey only
   3. http strict transport security: yes
3. Created user for domain
4. Connected via FTPS successfully for user/domain
5. Created directory for ssh keys under domain home directory, copy pubkey from user machine to file 'user.pub'
6. Go to 'User > Manage Keys > Add Key' and set name and path to 'user.pub'. Save.

When attempting to login I just get a username/password error/permission denied error. I'm I missing something here? Thanks for any advice!