United Airlines ordered a ground-stop this morning for all U.S. departures because of a computer glitch, and though the airline has resumed service, delays are sure to follow.

“We experienced a network connectivity issue. We are working to resolve and apologize for any inconvenience,” the airline said via Twitter.

According to FAA, all domestic airports and facilities were affected.

CNN reports that the issue began before 9 a.m. ET and included United and United connection carriers, including United Express. The connection airlines have been released from the ground stop, but United flights remained grounded until a little after 10 a.m.

United urges travelers and agents to check their websites for delays and any possible cancellations.