Disconnect it. Plug it back in. Go to the office and tell the master clock to reset all the clocks. It sounds like it is searching for guidance from the master unit.
these people may be able to help specifically if you don't have instructions for the master unit.
This is the way I did it when we have all the clocks in a hundred room hotel to change when the clocks change in the UK. I went back to the same hotel 35 years later and asked if I could see when the cupboard where the clock was reset, and the unit was still there, albeit not working. It was replaced for a more modern system, of putting clock radios in rooms.