United Airlines has grounded flights nationwide on Wednesday night due to an issue with its weight and balance computer system.

United Airlines resolved a “technology issue” that triggered a ground stop for the carrier’s flights at major U.S. airports Wednesday evening that led to hundreds of delays and some cancelations, although the airline was still tackling residual delays triggered by the outage.

A tech outage led United Airlines to ground flights nationwide Wednesday night, and even with the issue now resolved, over 1,000 flights have been delayed and dozens canceled.