It is unlikely for several reasons.
First, the flare reportedly peaked on Friday at 7:28 p.m. EST. Wisconsin is in the Central time zone, so that would have been at 6:28 PM local time. The reported Muzak outage was “for a while on Saturday”, which would have been sometime between about six to thirty hours later.
So, to be pedantic, effects of the flare would have to be evaluated on an immediate basis as well as on a delayed basis.
Immediate effects - unlikely: The immediate effect of the flare was a radio blackout on HF frequencies (roughly 10 MHz and below) over Australia and the South Pacific (Australia has several time zones, Sydney for example is maybe 16 hours ahead of NY, so it would have been close to noon time there with the sun relatively high overhead on almost the Solstice marking the beginning of summer in the Southern Hemisphere, thus the increased ionization leading to high levels of absorption of HF signals for a relatively brief period), however HF frequencies are not involved in Muzak distribution. Moreover, the geosynchronous satellite(s) responsible for Muzak distribution to the US would have been in darkness at the time of the flare, so it is unlikely that there would have been any immediate effect of the flare on the Muzak satellite network or ground station(s), which would also have been in darkness (antenna pointing for the Muzak feed from Wisconsin from the Galaxy 3C satellite, for example, would be almost due South).
Delayed effects - unlikely: While the flare reportedly generated a CME (coronal mass ejection), the CME was not aimed directly at Earth, so at the most a minor geomagnetic storm might be expected, but since geomagnetic storms are triggered by slower-moving charged particles rather than the burst of X-rays and UV light that triggered HF blackouts, any resultant geomagnetic storm was not likely to have been experienced during Saturday, since CME effects may take three to five days to reach the Earth. Also, the direct effects of a geomagnetic storm on a satellite are likely to be more noticeable on a satellite in low-Earth orbit rather than on a much-higher orbiting geosynchronous satellite (although permanent damage from charged particles is a risk for such satellites).
So, that’s why I suggested that a link between the solar flare and the reported temporary Muzak outage was ‘unlikely’.
Although it is possible that I am incorrect about the geosynchronous satellite(s) being in darkness, as it appears that for those satellites darkness would occur during a period close to the Equinoxes, not close to the Solstices which I had expected, so I’m off by six months.