Unable to retrieve query output of MongoDB using Go

I'm using Go and Gin. Generally I'm connecting my local MongoDB instance from code. Yet the problem is I'm calling FindOne to check if an email exists in DB. Still it's not returning any data.

The Db file looks like this

package database

import(
	"fmt"
	"log"
	"time"
	"os"
	"context"

	"github.com/joho/godotenv"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"bootcamp.com/server/configs"
	)

func DBinstance() *mongo.Client{
	err := godotenv.Load(".env.dev")
	if err!=nil{
		log.Fatal("Mongo ENV Load status >>>> ", configs.ENV_LOAD_ERROR)
	}

	MongoDb := os.Getenv("MONGODB_URL")

	client, err:= mongo.NewClient(options.Client().ApplyURI(MongoDb))
	if err != nil {
		log.Fatal(err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	err = client.Connect(ctx)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(configs.DB_CONNECTED)
	return client
}

var Client *mongo.Client = DBinstance()

func OpenCollection(client *mongo.Client, collectionName string) *mongo.Collection{
	var collection *mongo.Collection = client.Database("dev-camper-go").Collection(collectionName)
	return collection
}

and I'm taking that in services to call collection. which looks something like this.

var usersCollection *mongo.Collection = database.OpenCollection(database.Client, "user")
var userModel models.Users

Below is the method to call DB,

func CheckIfUserExists(emailId string, ctx context.Context, cancel context.CancelFunc)  error {
	userExists := usersCollection.FindOne(ctx, bson.M{"email": "billi@gmail.com"}).Decode(&userModel)
	fmt.Println("Data From Services >>>>> ", userExists);
	return userExists
}

but it's printing

Data From Services >>>>>  mongo: no documents in result

But as I hard coded data to DB, this should return data. Just adding one image for this

Can anyone please help me to understand the issue. As i'm learning Go, I've less understanding of these topics.

Full code on GitHub link: https://github.com/SohamRoyNoel/go-bootcamper-api

Please help me to fix this. Thanks.

Looks like a typo.

- var usersCollection *mongo.Collection = database.OpenCollection(database.Client, "user")
+ usersCollection := database.OpenCollection(database.Client, "users")

Note: According to the screenshot, the name of the collection should be users, not user.

PS: when you encounter an issue, try to reduce your program to a minimal reproducer. It will make it easy to find out what's wrong. For example, I will reduce the program to this one:

package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

func main() {
	client, err := mongo.NewClient(options.Client().ApplyURI("mongodb://localhost:27017/dev-camper-go"))
	if err != nil {
		log.Fatal(err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	err = client.Connect(ctx)
	if err != nil {
		log.Fatal(err)
	}
	collection := client.Database("dev-camper-go").Collection("user")
	var userModel struct {
		ID    primitive.ObjectID `bson:"_id"`
		EMAIL *string            `json:"email" validate:"required,max=100"`
	}
	userExists := collection.FindOne(ctx, bson.M{"email": "billi@gmail.com"}).Decode(&userModel)
	fmt.Println("Data From Services >>>>> ", userExists)
}

If I can reproduce the issue with this one, good, I have narrowed down the issue to several lines. If I can not, I will add back codes a small piece by a small piece until I can reproduce the issue.