(CNN) -- An internet service outage for some Comcast customers on the East Coast eased early Monday, the company said.
"Late this evening, our engineers identified a server issue that was affecting only Internet service in Greater Boston and DC/Beltway areas," Comcast spokesman Charlie Douglas said.
Shortly after midnight Monday, the problem appeared to be resolved. Comcast engineers "are reporting service is working properly again," Douglas said.
He added that it was "unclear" how many Comcast customers were impacted in total. Engineers were working to determine the disruption's cause, he said.
Twitter lit up with tweets from irked Comcast customers. Many of them offered advice on how to change computer internet settings to circumvent the outage.
The outage came on the eve of Cyber Monday, the annual online equivalent of Black Friday when internet retailers roll out their bargains for holiday shoppers.