And in case some can't access the status link;
"Zen Web Sites
The following new Zen Web Sites incident has been identified. Further information is detailed below.
Outage on Zen Websites(New)
Outage - Emergency maintenance
Start: Sat, 19/09/2015 14:00
Update: Sat, 19/09/2015 16:30
We are currently experiencing an issue with the Zen public facing websites.
This is affecting the following:
Online Invoice Payment (secure.zen.co.uk)
Customer Portal (https://portal.zen.co.uk)
Partner Portal (https://www.zenpartner.com)
Our engineers are investigating and further updates will be posted here when available.
Zen regret any inconvenience this may cause.
Posted: Sat, 19/09/2015 16:00 by Tuseef Shah"