Alaska Airlines operates 238 Boeing aircraft, 87 Embraer planes, and 45 additional planes through Horizon Air. The Seattle-based company is the fifth-largest airline in the U.S., serving more than 44 million passengers annually.

Alaska Airlines has resumed flights after the failure of a critical piece of hardware forced the airline to ground all its planes for approximately three hours, but the effects will linger into Monday, the company announced.

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.