Keep things PG-13, don’t harass other players, don’t click suspicious links, don’t cheat, and don’t buy in-game currency using real money from a 3rd party seller. If you have ever played an MMO in your life, you usually know what is expected of you.
Terms of Service…those long lists that so many of us just don’t bother reading because they all basically say the same things.
Literally all that and more was going through my head as I tried over-and-over to log in (fruitlessly), and then had no choice but to submit a ticket to Square Enix’s Support Team.