What's with the 90000 error?

I've been playing this game for 1.5 weeks now and didn't have a single DC or anything like that.
Now however, I am not able to connect to NA/EU gateway 95% of the time and when I can log-in I am thrown out of the game showing the 90k error.
It seems I am not the only one having the problem.
Since the search function in this forum is not really that well (or I am just a noob and can't use it properly) I couldn't find anything that helps.
Is there a way for the user to fix this?

It seems that there have not been any further posts about this concern being an ongoing issue. Because of this, we are considering it to be resolved. If this does continue to be a concern, please create another thread to further discuss resolutions or contact the Support Center at support.na.square-enix.com for assistance.