From Launch Control:

The launch of a Minotaur I launch vehicle from Space Launch Complex-8 here has been delayed due to a
power issue affecting mandatory range safety equipment.

During the countdown, Western Range controllers observed a power fluctuation on a transmitter used to maintain positive control over the launch vehicle throughout range operations.

“Safety is our number one priority, so we are analyzing the situation and taking every necessary precaution,” said Col. Richard Boltz, 30th Space Wing commander and launch decision authority.

The launch has been rescheduled for 4:26 a.m. (PST), Feb. 6, pending resolution of the power issue.