HARRISBURG - Pennsylvania residents will have an extra day to file their state personal income-tax returns because the Department of Revenue website - as well as the websites of many other state agencies - went dark for several hours Monday afternoon due to a technical breakdown.

State officials had not pinpointed the cause of the problem as of late Monday afternoon, but did say it was not the result of a cyber attack and ruled out foul play.

Residents will be able to file their returns until midnight Tuesday without penalty, Revenue Secretary Dan Meuser said.

"Since Pennsylvanians were unexpectedly unable to access padirectfile, tax forms, and our Online Customer Service Center on our website for a few hours [Monday], in the interest of customer service, we won't penalize anyone who files a return by midnight Tuesday, April 16," Meuser said in a statement.

He said the department became aware of the website issues around 1:30 p.m., and website access was restored shortly before 5 p.m. Department spokesman Elizabeth Brassell could not say how many people had reported problems filing returns Monday, but said that the department decided to allow an extra day to accommodate any residents who may have been unable to file electronically or to get the information they needed to file taxes.

The Revenue Department wasn't the only state agency experiencing problems. About 40 other departments, commissions, and board saw their websites go dark because of technical issues, administration officials said.

Dan Egan, spokesman for the Office of Administration, said the state websites affected were ones that operate on the same server, resulting in an error message when users tried to access the site.

He said the state has experienced website problems in the past, often on a smaller scale than Monday's outage. He blamed "an aging technology nearing the end of its life."

"But we are looking to move away from that in the near future," Egan said. He said the state had contracted with an outside company, Kansas-based NIC Inc., to begin managing its websites.

Egan said 28 other states use NIC, which in Pennsylvania will manage everything from the state's software to its servers, web design, and security of its sites.

Contact Angela Couloumbis at 717-787-5934 or acouloumbis@phillynews.com, or follow on Twitter @AngelasInk.