"This is the busiest tax day of the year, and the IRS apologizes for the inconvenience this system issue caused for taxpayers," said Acting IRS Commissioner David Kautter in a press release. "The IRS appreciates everyone's patience during this period. The extra time will help taxpayers affected by this situation."
U.S. Treasury Secretary Steve Mnuchin told reporters in New Hampshire that the IRS website crashed due to "a high volume technical issue." It is unclear how many people were impacted by Tuesday's outage, but, according to ABC News, about 5 million tax returns were filed on the final day of tax season last year.