There’s a troubling report for people who ordered their Christmas gifts online this year: UPS is struggling to handle all the orders.

There has been a tremendous surge in online sales, resulting in a larger than expected holiday volume that is resulting in disruptions and possibly delays that could keep packages from being delivered on time, according to a Wall Street Journal report.

The rate of on-time deliveries dipped to 91 percent for UPS ground packages, compared to a 97 percent rate at the same time last year. And it’s not just UPS: FedEx also saw their rate dip to 95 percent.

UPS is struggling not only with an exceptionally high order volume, but also extra pickups and a short supply of staff and equipment. The company is scrambling to address the problem, assigning managers at their corporate headquarters in Atlanta to help speed times at delivery centers across the country.

Consumers spent big during this year’s Thanksgiving holiday weekend, shelling out $4.45 billion online. Black Friday sales were up 14 percent compared to last year, and half of that shopping was done on mobile devices.

UPS is struggling more than other delivery companies because it does more residential deliveries than FedEx or the U.S. Postal Service.

The concern is that we may have a repeat of 2013, when UPS and FedEx became so overloaded they were unable to complete many deliveries on time. But they are also concerned about going too far, as UPS did last year when it spent a ton of money on hirings compared to the volume they had to deliver — it is estimated that they overspent by $200 million.