CNN  —  A ground stop that earlier paused Alaska Airlines’ flights has been lifted. “This morning we experienced an issue while performing an upgrade to the system that calculates our weight and balance. Out of an abundance of caution, we requested a ground stop for all Alaska and Horizon flights, which was instituted at approximately 7:30am PT. The issue was mitigated and the ground stop for Alaska and Horizon flights expired at 8:30am PT,” the airline said in a statement to CNN. The Federal Aviation Administration had earlier grounded Alaska Airlines flights nationwide at the airline’s request. The airline statement adds: “We have begun releasing flights. Residual delays are expected throughout the day. We apologize for the inconvenience and encourage guests to check the status of their flights on alaskaair.com or the Alaska App prior to heading to the airport. “