This server has the characters saved to your username rather than CDkey, as long as your username is exactly the same as you used before your character list will show.
Go to Options, Game Options, Client: Player Name if you need to redo it. If they aren't there still, you don't have the name right (or OneDrive / Antivirus safe folders list pointing at your Documents folder has been turned back on and is messing up your file access)
If you can't remember your username make a tech request and they'll be able to let you know which one you used for your characters. After you've logged in, if your CD key is still the same you should be okay to continue, otherwise you'll need to use @login with the password set at char creation or make another tech request.