Hi Team, Please find below error for inserting document from .Net to MongoDb Collection.

‘69f2cd42-b6a4-418f-a4c2-ece3d719ed6f’ is not a valid 24 digit hex string.

Id Property is string GUID which is accepting when I am inserting document from MongoDbCompass or web Collection Explorer but whenever we insert the same from .net code, it generating exception.

Details Exception:

   at MongoDB.Bson.ObjectId.Parse(String s)
   at MongoDB.Bson.Serialization.Serializers.StringSerializer.SerializeValue(BsonSerializationContext context, BsonSerializationArgs args, String value)
   at MongoDB.Bson.Serialization.Serializers.SealedClassSerializerBase`1.Serialize(BsonSerializationContext context, BsonSerializationArgs args, TValue value)
   at MongoDB.Bson.Serialization.Serializers.SerializerBase`1.MongoDB.Bson.Serialization.IBsonSerializer.Serialize(BsonSerializationContext context, BsonSerializationArgs args, Object value)
   at MongoDB.Bson.Serialization.IBsonSerializerExtensions.Serialize(IBsonSerializer serializer, BsonSerializationContext context, Object value)
   at MongoDB.Bson.Serialization.BsonClassMapSerializer`1.SerializeNormalMember(BsonSerializationContext context, Object obj, BsonMemberMap memberMap)
   at MongoDB.Bson.Serialization.BsonClassMapSerializer`1.SerializeClass(BsonSerializationContext context, BsonSerializationArgs args, TClass document)
   at MongoDB.Bson.Serialization.BsonClassMapSerializer`1.Serialize(BsonSerializationContext context, BsonSerializationArgs args, TClass value)
   at MongoDB.Bson.Serialization.IBsonSerializerExtensions.Serialize[TValue](IBsonSerializer`1 serializer, BsonSerializationContext context, TValue value)
   at MongoDB.Driver.OperatorUpdateDefinition`2.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry)
   at MongoDB.Driver.MongoCollectionImpl`1.ConvertWriteModelToWriteRequest(WriteModel`1 model, Int32 index)
   at System.Linq.Enumerable.<SelectIterator>d__174`2.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at MongoDB.Driver.Core.Operations.BulkMixedWriteOperation..ctor(CollectionNamespace collectionNamespace, IEnumerable`1 requests, MessageEncoderSettings messageEncoderSettings)
   at MongoDB.Driver.MongoCollectionImpl`1.CreateBulkWriteOperation(IClientSessionHandle session, IEnumerable`1 requests, BulkWriteOptions options)
   at MongoDB.Driver.MongoCollectionImpl`1.<BulkWriteAsync>d__30.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
   at MongoDB.Driver.MongoCollectionImpl`1.<UsingImplicitSessionAsync>d__106`1.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
   at MongoDB.Driver.MongoCollectionBase`1.<UpdateOneAsync>d__107.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Core.User.Infrastructure.NoSql.MongoDb.User.Repositories.UserRepository.<AddAsync>d__4.MoveNext() in
            [BsonRepresentation(BsonType.ObjectId)]
            [JsonProperty("id")]
            public string Id { get; set; }
JSON working when inserting from MongoDbCompass:
        "_id": "69f2cd42-b6a4-418f-a4c2-ece3d719ed6f",
        "UserName": "SC1005",
        "EmailID": "[email protected]",
        "Password": "APt/zqxocK9haWvu5Iv8+NgWSUuWzep8HrFFRcSkrOveYsBVQDYn7YfxFRVE99R8Mw==",
        "FullName": "Pravin Yadav",
        "LastPwdChangedDateTime": "2021-08-09T12:54:05.62+05:30",
        "UserGroup": {
            "_id": "69f2cd42-b6a4-418f-a4c2-ece3d719ed6f",
            "GroupName": "Administrator"
        "UserVisibility": {
            "_id": "69f2cd42-b6a4-418f-a4c2-ece3d719ed6f",
            "GroupName": "Administrator"
        "ShowLocalLanguage": false,
        "CreatedDetails": {
            "UserId": "69f2cd42-b6a4-418f-a4c2-ece3d719ed6f",
            "SessionId": "69f2cd42-b6a4-418f-a4c2-ece3d719ed6f",
            "UserName": "SC1005",
            "Timestamp": "2021-08-09T12:54:05.62+05:30"
        public UserResponse(string id, string userName, string emailID, string password, string fullName, UserGroupResponse userGroup, UserVisibilityResponse userVisibility, bool showLocalLanguage, DateTimeOffset? lastPwdChangedDateTime, bool active, bool isDeleted, ActivityDetails createdDetails, ActivityDetails lastUpdatedDetails)
            Id = id;
            UserName = userName;
            EmailID = emailID;
            Password = password;
            FullName = fullName;
            UserGroup = userGroup;
            UserVisibility = userVisibility;
            ShowLocalLanguage = showLocalLanguage;
            LastPwdChangedDateTime = lastPwdChangedDateTime;
            Active = active;
            IsDeleted = isDeleted;
            CreatedDetails = createdDetails;
            LastUpdatedDetails = lastUpdatedDetails;
        [BsonId]
        [BsonRepresentation(BsonType.ObjectId)]
        [JsonProperty("id")]
        public string Id { get; set; }
        public string UserName { get; set; }
        public string EmailID { get; set; }
        public string Password { get; set; }
        public string FullName { get; set; }
        public UserGroupResponse UserGroup { get; set; }
        public UserVisibilityResponse UserVisibility { get; set; }
        public bool ShowLocalLanguage { get; set; }
        public DateTimeOffset? LastPwdChangedDateTime { get; set; }
        public bool Active { get; set; }
        public bool IsDeleted { get; set; }
        public ActivityDetails CreatedDetails { get; set; }
        public ActivityDetails LastUpdatedDetails { get; set; }
@Pravin_Yadav  you need to decorate the model with this attribute [BsonId].
 public class UserResponse
            [BsonId]
            public string Id { get; set; }
            public string UserName { get; set; }
        static void Main(string[] args)
            MongoClient dbClient = new MongoClient("mongodb://localhost:27017");
            var database = dbClient.GetDatabase("test");
            database.GetCollection<UserResponse>(nameof(UserResponse)).InsertOne(new UserResponse { Id = Guid.NewGuid().ToString(), UserName = "Test User" });          
and DotNet 5

    private readonly IMongoDatabase _db;
    private readonly IMongoCollection<Application.User.Responses.UserResponse> _collection;
    private readonly MongoClient _client;
    public UserRepository(MongoClient client)
        _client = client;
        _db = _client.GetDatabase("UserDatabase");
        _collection = _db.GetCollection<UserResponse>("Users");
    public void Add(UserResponse item, CancellationToken cancellationToken)
        _collection.InsertOne(item);
      
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