Herb Schaltegger wrote:
[...]
It was a problem with ground-level wind gusts exceeding the 33 mile
per hour limit within the last few minutes of the count.

As well as during most of the rest of the launch window.

And today there seems to have been a power outage in the control
room(s).

Space.com says "New Horizons is now slated to launch no earlier than
Jan. 19 at 1:08 p.m. EST (1808 GMT), though it has a launch window that
extends for one-hour and 59 minute launch window."

/dps\