Error i2501 on every service

[Lurcainne]

I have been greeted by Error i2501 on so many attempts for a week now.
Tried to enter game time card, got the error
Tried to buy mount on the optional store, got the error

I have experienced this before so I know some alternatives solution--
BUT
After I tried many alternatives like using phone connection, went incognito, waited 24 hours. even switching browsers,
I even tried buying crysta, through paypal, and still the error persists, there, every time.

Some sources say that it is because I'm on EU region account and I am not living on EU
But is it really that strict? Do I really need to live on the region to be able to play?
My credit card works fine, I always use it to purchase stuffs for FFXIV, even my recurring sub. Why now? Why does the error persist?

My sub expiry date is coming closer and I'm so scared this will be the end of my sub if the issues don't get resolved.

UPDATE:
I EVEN GOT ERROR WHEN ENTERING THE ENDWALKER ACTIVATION CODE
WHAT THE HELL