Pennsylvania’s online system for registering to vote and applying for and tracking mail ballots crashed over the weekend, triggering an outage that stretched for more than 40 hours and prompted frustration from voters weeks before critical election deadlines.

State officials managed to restore the site Monday morning and blamed the problem on an equipment failure at a data center run by an outside contractor. They did not believe any data had been lost or that malicious physical or cyber activity was behind the outage.

Secretary of Administration Michael Newsome said the outage began at roughly 5:30 p.m. Saturday. The outage also affected online services at other state agencies, including the revenue and human services departments, as well as the state Liquor Control Board.

But with voter registration and mail ballot application deadlines looming, and amid President Donald Trump’s escalating attacks on how votes are cast and counted in Pennsylvania and elsewhere, many took to social media over the weekend to criticize the extended outage.

The Oct. 19 deadline for registering to vote is just two weeks away. The deadline for requesting mail ballots is Oct. 27. A new state law allowing any voter to cast their ballot by mail, coupled with coronavirus fears of voting in person, has led to a huge increase in mail voting this year. About three million Pennsylvanians are expected to vote by mail in the general election.

County elections officials and voters have regularly complained about a variety of problems with the Pennsylvania Department of State’s voter services website and the state’s voter database, which officials use to process registrations and ballot applications.

The back-end system, known as SURE, was built in the early 2000s and has been tasked with handling more and more services — online voter registration in 2015, online ballot applications last year — while officials experience a massive surge in mail ballot requests.

At times this year, the system has slowed to a crawl or come to a complete halt, leaving election offices unable to register voters or process ballot requests.

That became especially obvious Tuesday, when Philadelphia officials held a celebratory news conference to open seven satellite elections offices for a new form of “early voting” using mail ballots — and the system crashed moments later, leaving voters waiting in frustration.

Voters have been anxious waiting for their mail ballots to arrive, after the printing and sending of ballots was delayed by a legal challenge that ended with the state Supreme Court kicking the Green Party’s presidential ticket off the ballot. Counties are now well into the process of sending ballots to voters, as voting gets underway in the 2020 election.

Robert Sullivan said he and his wife were waiting for their mail ballots to arrive at their home in the Olde Kensington section of Philadelphia. He’s been checking the status of his ballot online, and his experience with the site, up until this weekend, has been “excellent,” he said.

But on Saturday evening, the site “wouldn’t completely load,” he said, and he encountered a similar issue Sunday morning.

“This is a year where you have to work really hard to stay calm about what might be the very mildest server hiccups,” Sullivan said, adding: “I want the machinery of the election to work as flawlessly as possible.”

The issues with the state’s system are not normally so public. While counties' frustrations with SURE are widely held, they normally do not affect voters.

When the system went down during the last day to register to vote before the 2020 primary, for example, some county elections offices simply gave up, deciding to finish processing the voter registrations the next day.

That didn’t directly affect voters, who were not aware that their registrations were processed the day after the deadline. But the technical glitch caused a disruptive ripple effect during one of the busiest times for county elections offices.

Secretary of the Commonwealth Kathy Boockvar, whose Department of State oversees elections, acknowledged the intermittent connectivity issues with both the system used by county elections offices and the voter services website during a news conference last week. She said technicians were actively looking at ways to improve the system as Election Day nears.

“While the exact cause is not yet known, there’s no evidence present at this time to suggest any malicious activity,” she said Wednesday. “We will continue, of course, to keep investigating.”

During outages, people can still download and print paper voter registration forms and mail ballot applications, request them at county elections offices, or call 877-868-3772 (877-VOTESPA) to have them sent by mail.

Staff writer Catherine Dunn contributed to this article.