Arduino freezing after few second running

Hello i have the same issue for my project… when my program is running after few second, it will freeze immediately…
Then, i need to restart the program again…
Is there anyone who can help me?

19_Agustus_2019.ino (6.05 KB)

Please post your code inline so we can see it. It may help if you read the sticky post foe new users. Good luck.

if (hum <= 56) {                     // if set value more than air humidity
      digitalWrite(RelayPIN, HIGH);      // power on
      } else if (hum >= 58) {            // if not
      digitalWrite(RelayPIN, LOW);       // power off
    }

Will hum never be 57? Or 56.5?