Elections officials in Pennsylvania are being inundated with complaints from first-time and absentee voters having difficulty registering to vote or requesting a mail ballot, fueling anxiety in the critical swing state just as the 5 p.m. Monday deadline approaches to join the voting rolls in time for the November election.

College students in at least three counties in Pennsylvania who attempted to register to vote online had their applications rejected and were notified that they must provide documentation in person or by mail to meet the Monday deadline, raising concerns among voting rights advocates that an unknown number of students may not be able to register in time.

Meanwhile, other voters are receiving rejection notices for their absentee ballot requests without a clear explanation. County officials said the vast majority of these rejections were due to duplicate requests. The voters had already requested a general election ballot when they were applying to vote by mail for the primary election, so they didn’t need to request one again for the fall.

While these voters who submitted duplicate requests will still be able to cast their ballot by mail, several county elections officials said their offices have been flooded by calls from confused voters.

“When we get so many calls, it’s almost like a denial-of-service attack. We can’t get anything else done here,” said Marybeth Kuznik, elections director of Armstrong County, which has about 44,000 registered voters. “I’m a full-time office of one, with two to three part-time helpers at different hours of the day. It breaks my heart because I really want to speak with every voter. It’s just impossible.”

These challenges come as Pennsylvania, one of the most closely watched states for the November election, grapples with heightened voter interest in a year it is for the first time allowing anyone to vote by mail in a general election. A law enacted this year eliminated the requirement that voters wanting to cast ballots by mail provide an acceptable excuse.

But the new law comes as voters are grappling with problems with the U.S. Postal Service and the chaos around the pandemic. These factors have heightened the stakes for mail-in voting, as voters are increasingly opting to register online or cast their ballots by mail to avoid potential mail delays or exposure to the novel coronavirus at the polls.

“The state was not prepared for this, as you can well imagine,” said Eileen Olmsted, communications director for the League of Women Voters of Pennsylvania.

“This is a new law for us, so it’s brand new for most people in Pennsylvania to be voting by mail,” she said. “Secondly, there’s covid-19, and third, the tremendous interest in this election and the fact that on top of all of that, Pennsylvania is a swing state, and everybody knows it’s a swing state. We’re kind of being put on the spot here.”

The problems are a potentially troubling sign as lawyers for President Trump and Democratic challenger Joe Biden are already flooding into the state, anticipating a close election that could hinge on the outcome in Pennsylvania. Trump and his fellow Republicans have already seized on sporadic voting problems across the country to cast suspicion on the election system and lay the groundwork for legal challenges.

Pennsylvania is approaching 9 million registered voters and had approved roughly 2.7 million mail ballot applications as of Friday morning. All 67 counties in Pennsylvania have started sending mail ballots to voters, and more than 683,000 of those ballots have been submitted, including 510,435 from Democrats and 116,135 from Republicans.

As voters flood county election offices with calls, they have the option of checking online using the state’s ballot tracking tool to see if they’ve previously submitted an application for a mail ballot and whether it was accepted. The last day for voters to request their absentee ballots for the general election is Oct. 27.

The online registration problem has confounded college students, some of whom are scrambling to go to their county offices by end of business day Monday to rectify any problems in person.

Those registering online to vote for the first time in Pennsylvania must upload their signature electronically. But several students said they found out after submitting their application — in some cases, weeks after they filled out the online registration — that their signatures were inexplicably rejected.

Janae Bacchus, an 18-year-old freshman at Carnegie Mellon University in Pittsburgh, repeatedly received an error message when she tried to upload her signature online. She then received a message that she would need to print out her application and mail it in, or drop it off in person, so she mailed it in.

“It was definitely inconvenient and it was frustrating, because I think there are a lot of people registering to vote last-minute and expecting to be an automatic process, and they find out they need to mail something,” she said.

Dave Voye, elections division manager of Allegheny County, where Pittsburgh is located, said the county is aware of this issue and “elevated it to the state for resolution. We are currently awaiting guidance from the Department of State.”

It is not clear exactly what is causing problems with the online registrations. One student said she was told that signatures uploaded from cellphones were showing up as a blur. Another was told that their application was rejected due to a “glitch” in the system.

One student at the University of Pennsylvania, located in Philadelphia, submitted her voter application on Sept. 22, but received an email on Oct. 12 that it was declined, without a clear explanation. It turned out to be another instance where the voter’s signature was not processed, requiring the student to mail in her application instead.

In a statement, the Pennsylvania secretary of state’s office said there were no glitches creating problems with the state’s system, and that counties are responsible for verifying the eligibility of voters who apply online.

As for people struggling with the ballot request process, Department of State spokeswoman Ellen Lyon said that “undeniably, Pennsylvania voters are still learning how it works and what to expect.”

“Some voters may have forgotten that they opted to be put on the annual mail ballot list when they applied for a ballot for the June primary. When voters choose to be added to this list, they automatically receive ballots for all elections in that calendar year and do not need to reapply for each election that year,” Lyon said in a statement.

Suzanne Almeida, acting executive director of Common Cause Pennsylvania, said she is aware of the technological challenges voters are facing as they try to register online and has petitioned the state to address it.

“There are things that DOS [Department of State] can do to make sure those people are registered, and my understanding is they are taking those steps,” she said, adding that the situation is “not perfect” and is “the kind thing that could make it more difficult for folks to register to vote. For someone who is on the fence, they may decide not to bother.”

Pennsylvania Secretary of the Commonwealth Kathy Boockvar has urged the public to consider using other ways to register to vote or request a mail ballot if they run into trouble.

She noted Friday that a data center outage shut down the state’s online voter registration for about a day and a half earlier this month, calling the failure “not acceptable” but adding that other methods for registering to vote remained “completely valid” during that period.

“I want to remind everybody: You have multiple ways of applying to vote,” Boockvar said during a virtual news conference. “You can use any of them. Again, just get it in by 5 p.m. on Oct. 19.”