Thanks RandomlyClicking, your message summarize the most common reasons for using “some issues” instead of specific reasons. As we also need to coordinate and translate our messages to several languages, I took the decision to be vague and push the message out as soon as possible, warning everyone 30 minutes before the servers were down instead of delaying communication and giving a short time before the restart.
This said, sadly this time there is not much we can communicate about the reasons for this restart as it was caused by some technical stuff in the backend of the game.