Internet service provider PlusNet suffered a complete power outage in its primary data centre early on Thursday morning.
According to PlusNet, the outage occurred at 1am, knocking out most of the ISP's internal systems, portals and email.
An update published on PlusNet's user site late on Thursday morning suggested that "most customer-affecting services should be working again", but noted that "some customers may have requested account changes or password alterations during this outage [and] any customer that had requested this should check their accounts to ensure the change occurred correctly".
Users' ability to collect email was affected by the outage until the early afternoon, when a fresh update claimed all email-authentication issues had been resolved.
In the last two years, PlusNet has suffered several mishaps with its customers' emails: in 2006, the ISP irretrievably lost around 700GB of emails due to human error, and, in 2007, it lost more when a new spam appliance was installed.
Also in 2006, a power outage at a Docklands co-location centre temporarily knocked PlusNet offline, and, in 2007, many of its customers suffered a spam deluge after their email addresses were stolen — the theft itself possibly occuring as far back as 2005.
The cause of the latest outage is yet to be determined. PlusNet had not responded to a request for comment at the time of writing.
PlusNet was bought by BT in November 2006, largely because of the quality of its customer-relationship management systems.