Proxmox ve suddenly unreachable

Hi community,

I've got a problem with my proxmox ve. I just can't reach it anymore under its ip-adress (witch is the 192.168.1782/8006), the curious thing about it is that I've already used it to build a LAMP-system on Debian installed my owncloud and everything worked fine, I even connected to no-ip. But 3 days ago I just could't reach the webinterface or the website.
I don't konw what to do now, pls hep. :rolleyes:

Keksgeber