Hello, that board has a control that protects it from overloads or involuntary interruption of the power supply.
Leave it connected and wait about 8 minutes to see if the compressor starts.
Click on the link to exit the user instruction manual, on page 20, in the section STARTING THE APPLIANCE, explain it more clearly.
Greetings and luck.
https://www.manualslib.com/manual/1137824/Ariston-Ups-1701-TF.html?page=20#manual