I am trying to pre-order and check out the digital download, but it keeps saying my account credentials are invalid. Even though I can log in in a different window. Anyone else having this issue?
I had the same problem. You have to log into the SE website, fill in a few extra credentials, then you can go to the store.
Login here: na.square-enix.com
FFXIV: Raxion Gunsoul - Brynhildr - 50PLD 50SMN 50SCH 50DRG
WoW: Raxion - Greymane- 90 Druid
FFXI: Nion - Asura - 99 BLU, PUP, SMN, DRG, PLD 50+ DNC, NIN, MNK, THF, WHM, SAM, WAR