My brother played the trial version on PC a couple years ago, but ended up not getting the game at that point. Recently, with the unlocking/expansion of the trial version, he wanted to try it out on PS4. However, when he tries to login, he gets a message "there's is already a service account" or something to that effect, and he's not allowed in the trial.

Can anyone help on what's going on and how to get into the trial?