Some Yahoo users said they began to notice problems early this morning.
"I can't get into my Yahoo mail box or my personalized Yahoo start page," said Jason Typrin, a Yahoo account holder in the Los Angeles area. "I haven't been able to get in since this morning--about 9 (a.m.) when I first tried."
A Yahoo representative confirmed troubles with the network but said service had been restored. The representative said problems stemmed from the company's service providers, including Global Center.
Global Center spokeswoman Secret Fenton said the cause appeared to be a fiber cut in the network backbone run by parent Global Crossing. She said the cut appeared to be located in the San Francisco Bay Area but added that the investigation is ongoing.
"The network does work. There is not a point of failure," she said. "The traffic has been rerouted, but that can take a little time."
Internet performance measurement firm Keynote Systems said Yahoo was hit with a major breakdown between 1 p.m. and 2 p.m. PT. Keynote spokesman Daniel Todd said Yahoo Finance and Yahoo Travel appeared to be completely unavailable to outside consumers for about a half hour, but he said the services were restored soon after that.
He said the main Yahoo Web page was not affected.
News.com's Paul Festa contributed to this report.