Are your main and alt on the same server? If they're on different servers, you'll need to change to the right one before you'll see your character. This is actually a two part process as you have to first be on the right data center before you can even select the right server.

On the first window after login (the one that has "Start", "Select Data Center", "View Opening Movie", or something like that - not there to check right now) go to the option to set your data center. For instance, to log in as your profile character, Sakura Nujab, you'd need to select the Aether Data Center because that's where the Faerie Server is.

Once that's correct, choose "Start" to get to the Character Selection and Creation screen. In the top right of that screen are buttons for "World" and "New Character". Choose "World" and set it to the server your character is on (Faerie in the case of Sakura Nujab). Once you're on the right world, your character(s) should be available to select.