Character name not available across several DCs and servers

Date & Time: 3/30/2021
Frequency: Common
World name: Aether
Character name: Nyvia Hlaethar
Steps:
1. Purchased two separate name changes in Jan2021 and Apr2020 to obtain the name Nyvia Graeson. Name was not taken on the lodestone prior to purchasing the name changes, but character creation gave the error that username was not available with error 1003 on the bottom right corner. Googling the error gave me outdated results from 2010.
2. Attempted to use the name Nyvia Graeson on each Aether server with the same unavailable results. I have never received the error "Username is already taken." Just that it's not available. I tried to also use the name Nyvia Graeson on several randomized servers on Primal, Crystal, Light, and Chaos with the same results.
3. I initially settled on the name Nyviia Graeson which was successful but was unhappy because I had to settle with it after already purchasing the name change assuming I would be able to use Nyvia Graeson. I afterwards purchased another change to use the name Nyvia Hlaethar. Both Nyvia and Graeson are useable under other combinations, but Nyvia Graeson is unavailable and I have no clarity as to why, and I would assume after what little research I was able to do that it is an in-game bug.

There's some names that trigger the censor gods, I believe. That may have inadvertently been one of the names. (Take my words with a HUGE grain of salt, I'm just guessing here.)

Three letters either side of the space are being objectionable to the censor, I think...

They've erred very much on the strict side of the filter. The text log censor can even try to cover up things like parts of world names if it combines with the following word into something on their banned list.

What about "Greyson" as a surname? It maintains the sound and you can keep using the forename spelled as you want it.

I think Iscah has the right of it - it's the obscenity filter not seeing the space between the names and detecting a resulting name of a well-known male impotency medication and thus blocking your name choice accordingly (it might seem a bit pendantic, but that's obscenity filters for you).

So basically your desired name has unfortunately become a victim of the 'Scunthorpe Problem' where a seemingly innocent name or word.... turns out to feature within it's letters something else (as people often use this very trick to actually beat obscenity filters, it's why they're so strict about this).

Unfortunately there isn't anything you can really do except try another name.