Tens of thousands of Virgin Media customers lost email service for 48 hours last week after a spam attack on its email supplier, Tucows.
The outage was probably caused by an attack on Tucows's OpenSRS email service, according to Virgin Media. "Since late Tuesday evening some customers on our Virgin Media DSL service may have been unable to access email or webmail," the company said. "This was due to a suspected spam attack suffered by our email supplier, which also affected a number of other ISPs. No customers on our cable service were affected."
The outage was remedied approximately 48 hours after it occurred, but Virgin Media customers were still being affected on Friday due the backlog of millions of undelivered emails. No emails were lost, said the company.
Elliot Noss, president and chief executive of Tucows, posted an open letter of apology to Tucows customers on Saturday. Noss expressed "deep sorrow" to Virgin Media for the outage on Tucows's Cluster A OpenSRS email service.
"First, and most importantly, we are sorry," Noss wrote. "I am sorry. I have been in this business a long time and do not know if I have ever been more sad about what we have done to you, to your customers and to how people think about us."
Noss wrote that as a result of the incident, Tucows would be making changes to its "monitoring, change management, emergency protocols and procedures, and operating efficiencies".
Tucows also apologised directly to Virgin Media's customers. "My message here would be simple, this was our fault not yours," wrote Noss.
A Virgin Media spokesperson declined to say whether the outage would affect Virgin's business relationship with Tucows. "Discussions are ongoing to ensure this doesn't happen again," said the spokesperson.
Tucows could not comment to ZDNet.co.uk at the time of writing.