Hi there Metalheads!
Our datacenter where we host our servers will be doing some maintenance on them, therefore the game servers will be somewhat unstable from 00:00 until 06:00am CEST. This will only affect the European servers.
If there is any downtime at all, we don't expect it to last longer than 15 minutes.
We apologize for the issue, and please let us know in the comments if you face any significant downtime during this period :)
As always, thanks for playing HMM - you rock.