MICS 2714 is producing 0PPM

I am not getting any output PPM for any gas measured. Please help me with my problem. I'm trying to read the following gasses:

H2 gas concentration:0.0000 PPM

CH4 gas concentration:0.0000 PPM
C2H50H gas concentration:0.0000 PPM
H2 gas concentration:0.0000 PPM
NH3 gas concentration:0.0000 PPM

using the following code:

float gasdata = mics.getGasData(H2);
 Serial.print("H2 gas concentration:");
 Serial.print(gasdata,4);
 Serial.println(" PPM");
 

 gasdata = mics.getGasData(CH4);
 Serial.print("CH4 gas concentration:");
 Serial.print(gasdata,4);
 Serial.println(" PPM");
 

 gasdata = mics.getGasData(C2H5OH);
 Serial.print("C2H50H gas concentration:");
 Serial.print(gasdata,4);
 Serial.println(" PPM");
 

 gasdata = mics.getGasData(H2);
 Serial.print("H2 gas concentration:");
 Serial.print(gasdata,4);
 Serial.println(" PPM");
 

 gasdata = mics.getGasData(NH3);
 Serial.print("NH3 gas concentration:");
 Serial.print(gasdata,4);
 Serial.println(" PPM");
 delay(1000);

 but somehow I'm getting 0 ppm for all the gasses. Please help me.