Why does replacing delay with millis outputs 0's?

Troubleshooting
1

I’ve implemented this tutorial Cloud Data Logger
In the tutorial, they are using a delay function. This messes with Blynk.
The internet said to take a look at millis. I did. I implemented.

The problem is with the old way of doing this (Like in the tutorial) with the delays, I was getting sensible values for temperature and humidity. Now(with millis) I’m getting zeros with them

What is wrong with my code?

    // #include "Ubidots/Ubidots.h"
    // #define TOKEN  "iNBZLODkcspwUVaEVExXolpBdAQtvQ"
    // Ubidots ubidots(TOKEN);


    #include "elapsedMillis/elapsedMillis.h"
    
    
    #include "blynk/blynk.h"
    char auth[] = "e10136e73eaf44b68c029c71439d00e8";
    
    #include "Adafruit_DHT/Adafruit_DHT.h"
    
    #define DHTTYPE DHT11
    #define DHTPIN 5
    
    const int lightPin = A0;
    
    int temperature,
        humidity,
        light;
    
    
    DHT dht(DHTPIN, DHTTYPE);
    
    bool success; // To check if Particle.publish is a success
    
    unsigned long previousMillis = 0;
    const long interval = 5000;

    void setup(void)
    {
        Serial.begin(9600);
        dht.begin();
        Blynk.begin(auth);
    }
    
    void loop(void) {
        Blynk.run();
        unsigned long currentMillis = millis();
        
        
        
    
        // Particle.publish(const char *eventName, const char *data, int ttl, PRIVATE);
        
        if(currentMillis - previousMillis >= interval)
        {
            previousMillis = currentMillis;
            
            float lightMeasurement = analogRead(lightPin);
            light = (int)(lightMeasurement / 4096 * 100);
            Particle.publish("Light", String(light) + "%", 60, PUBLIC);
            if(!success) { Serial.println("Could not publish Light measurement"); }
        
        
            temperature = dht.getTempCelcius();
            success = Particle.publish("Temperature", String(temperature) + " *C", 60, PUBLIC);
            if(!success) { Serial.println("Could not publish Temperature measurement"); }
        
        
            humidity    = dht.getHumidity();
            Particle.publish("Humidity", String(humidity) + "%", 60, PUBLIC);
            if(!success) { Serial.println("Could not publish Humidity measurement"); }
        
        }    
    }
2

@MustafaAdam Would you mind posting your “with delays” code? Have you gone back to your “with delays” code to determine if it still works?