Wells Fargo & Co on Tuesday said its online banking website was experiencing an unusually high volume of traffic that it believes stems from a denial-of-service cyber attack. “The vast majority of customers are not impacted and customer information remains safe,” said Bridget Braxton, a spokeswoman for the fourth-largest U.S. bank by assets. Customers who have trouble should try logging in again because the disruption is usually intermittent, she said.