TurboTax, the popular tax-filing software, went offline briefly on Sunday — the day before the filing deadline.

Users had problems entering data on the Web site, according to angry Twitter messages directed at the company. Some users complained about difficulty logging into the software.

“We’re having problems with TurboTax online. We’re in process bringing back the experience u expect. Updates 2 follow,” the company said on its official Twitter account Sunday evening.

Less than 10 minutes later, it issued another update saying the site was functional again. For those still experiencing problems, the company suggested closing browsers and opening the software in a fresh window.

The Web site was intermittently unavailable for some customers between 6:40 and 7:50 p.m. Sunday, TurboTax spokesperson Ashley McMahon said. The problem was caused by a “configuration setting” that needed to be adjusted to accommodate traffic, she said.

“We’ve resolved all the issues and we apologize for the inconvenience caused to customers,” she said.

Last-minute tax filers were not happy:

“Can’t log in. Get message that says Missing Security Question. been in and out of my account all day - this is new,” tweeted user H J McAllister.

“u cant! Not now!! #epicfail” tweeted user Emily Gunsberger.

Meanwhile, the technical glitch gave some who had filed earlier the opportunity to gloat: “Glad I finished mine this morning, yo,” said user KelleyLCarter.

More than half of all individual tax filings made online were made through TurboTax, according to a 2009 Government Accountability Office report. The company served 25 million customers last year, said McMahon.

The Internal Revenue Service does not have a specific provision for taxpayers to get an extension if they face software snags. If returns are filed later than the April 15 deadline, filers face a penalty unless they provide a reasonable explanation.