First, be sure that your server has not expired and has no expired abuse complaints.
To check out your expiry date, do the following:
1) Login to your My.snel.com Panel, click the relevant server on your dashboard and click 'Renew'
2) Be sure the days shown is a positive number bigger than 0.
To check out any expired abuse complaints, do the following:
1) Check you mailbox, be sure there is no abuse complaint listed with a deadline of 'Expired'
2) If you server is still down or offline, you should check your KVM.
To look at your KVM details, do the following:
1) Login to your My.snel.com Panel, click the relevant server and click 'KVM'
2) Click the link which goes to your KVM
3) If it does not load, try clicking 'Reset KVM' on the KVM page. If your KVM is down as well, please open a support ticket.