I created a second FFXIV account today as I want to play the story from the beginning on a new character without having all the veteran awards or locations unlocked as my main character.

In doing so I created a new account, added a new Windows service and paid for a 1 month subscription... however when I try to log into this account using the Steam client I get:

This service account does not have a valid FINAL FANTASY XIV license for this platform or your subscription has expired.
To register a license, please visit the FINAL FANTASY XIV: Mog Station (https://sqex.to/Msp).
My main account has Endwalker Early Access and has the Collector's Editions of most of the games, whereas this new account only has the basic regular editions of ARR through to ShB.

The only other difference between my main account and my new account is that under Account Type my main account has "Standard (Steam)" whereas my new account simply has "Standard".

Nothing during the sign-up process told me that I wouldn't be able to log in through Steam and I don't have enough space on my computer to have two complete versions of the game installed at the same time. Is there anything I can do to be able to log into my new account using the Steam launcher?