Alaska Airlines on Sunday, July 20 grounded all of its flights over a tech issue, but resumed its flights shortly after in the early hours of. However, the IT issue that caused the delays for travelers could end up causing more issues in the near future,

Alaska Airlines flights were back late Sunday night after an IT outage forced the company to ground all flights for three hours. From 8 p.m. until 11 p.m. PST, Alaska Airlines planes were on hold. The airline did not reveal the nature of the outage.

A hardware failure at an Alaska Airlines data center caused a system-wide “ground stop of flights” on Sunday night, the airline said. The airline has canceled more than 150 flights at various airports, including 64 Monday morning, with additional flight disruptions expected.