NEW YORK (CBSNewYork/AP) — All United Airlines flights nationwide were grounded for nearly two hours Wednesday morning due to computer problems.

In a statement, the airline said it experienced “a network connectivity issue.” It later said it was an internal issue and not an outside threat.

The computer problem, which affected the airline’s operations and reservation system, left many passengers scrambling.

PHOTOS: Computer Problems Ground United Flights

In Newark, Cindy Wolff was frustrated trying to figure out if her flight home to Asheville, North Carolina, was taking off. She said United left her in the dark.

“I didn’t get a text message. I didn’t get a phone call,” she told CBS2’s Hazel Sanchez.

The airline canceled 60 flights and delayed more than 800, affecting nearly 5,000 flights worldwide. The ripple effect is expected to be felt into Thursday.

Planes were unable to take off in Los Angeles and Chicago; passengers stood in long lines in Nashville, Tennessee, trying to get checked into to their scheduled flights.

In Burbank, California, airline agents were left no other option but to give out hand-written tickets.

The ground stop was lifted around 10 a.m., and United rushed to get flights moving again.

Alan Weiner and Barbara Burger were relieved to be back in New Jersey after being stuck on a plane in Fort Lauderdale, Florida, for an hour and a half.

“The scariest part was when we landed and we saw that it wasn’t just the computers for United, that it was The Wall Street Journal and the New York Stock Exchange,” Burger said. “So that’s kind of scary.”

Officials in Washington confirmed the United computer problems were not in anyway connected to the other outages.

“We hoped for the best when we got here,” another passenger at Newark airport said after the issue was resolved. “So far it looks like we’re going to be on time,  but we’re not sure once we get to the gate.”

The airline issued a video apology to its customers on Twitter on Wednesday afternoon.

“Let me apologize for the technology issues we had this morning,” said Sandra Pineau-Boddison, United’s senior vice president of customers. “We absolutely recognize this is a disruption to your travel, and we do appreciate your business and loyalty.”

During the outage, customers across the country took to Twitter to share their experiences.

United will be offering flight waivers on its website for customers who are unable to change their flight plans, Sanchez reported.

It is the second time in two months that the carrier has been hit by major technical issues.

The Chicago-based company had halted all takeoffs in the U.S. on June 2 due to what the airline described as computer automation issues. The Federal Aviation Administration used the same language to describe Wednesday’s outage.

United suffered a series of computer problems in 2012 after switching to a passenger information computer system previously used by merger partner Continental Airlines.

In each case, hundreds of flights were delayed. A number of high-paying business travelers defected to other airlines and revenue dropped.

“We don’t know everything behind this morning’s issues yet, but today’s incident underscores the sense that something is very wrong at United,” said Gary Leff, co-founder of frequent-flier website MilePoint.

Shares of United Continental Holdings Inc. declined $1.49 to $52.82 Wednesday.

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