First, confirm that your HVAC breaker is turned on.
Also, Wiser Air requires a 24 VAC power supply. If 120V/240V is applied for any amount of time, it is possible that the unit was damaged.
Wiser Air requires a common wire (the C terminal). If your previous thermostat did not have a common wire and a spare wire is not present, you can install the Wiser wire extender. Please see the Wiser Air installation guide.