System.NullReferenceException when trying to use the twitter client.

[Jivko1212]

I am getting the following exception when I run the twitter client:

System.NullReferenceException: Object reference not set to an instance of an object.
at Tweetinvi.Logic.JsonConverters.JsonLanguageConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer)
at Tweetinvi.Logic.JsonConverters.JsonPropertyConverterRepository.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
at Newtonsoft.Json.Serialization.JsonSerializerProxy.DeserializeInternal(JsonReader reader, Type objectType)
at Newtonsoft.Json.JsonSerializer.Deserialize[T](JsonReader reader)
at Tweetinvi.Logic.JsonConverters.JsonInterfaceToObjectConverter2.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) at Tweetinvi.Logic.JsonConverters.JsonPropertyConverterRepository.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) at Newtonsoft.Json.Serialization.JsonSerializerProxy.DeserializeInternal(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonSerializer.Deserialize[T](JsonReader reader) at Tweetinvi.Logic.JsonConverters.JsonInterfaceToObjectConverter2.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateList(IList list, JsonReader reader, JsonArrayContract contract, JsonProperty containerProperty, String id)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue, String id)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
at Newtonsoft.Json.Serialization.JsonSerializerProxy.DeserializeInternal(JsonReader reader, Type objectType)
at Newtonsoft.Json.JsonSerializer.Deserialize[T](JsonReader reader)
at Tweetinvi.Logic.JsonConverters.JsonInterfaceToObjectConverter2.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings) at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonConverter[] converters) at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonConverter[] converters) at Tweetinvi.Logic.Wrapper.JsonConvertWrapper.DeserializeObject[T](String json, JsonConverter[] converters) at Tweetinvi.Logic.JsonConverters.JsonObjectConverter.DeserializeObject[T](String json, JsonConverter[] converters) at Tweetinvi.Credentials.TwitterAccessor.ExecuteGETQuery[T](String query, JsonConverter[] converters) at Tweetinvi.Controllers.Search.SearchQueryExecutor.GetSearchTweetResultsFromQuery(String query) at Tweetinvi.Controllers.Search.SearchQueryExecutor.SearchTweetsWithMetadata(ISearchTweetsParameters searchTweetsParameters) at Tweetinvi.Controllers.Search.SearchQueryExecutor.SearchTweets(ISearchTweetsParameters searchTweetsParameters) at Tweetinvi.Controllers.Search.SearchController.SearchTweets(ISearchTweetsParameters searchTweetsParameters) at Tweetinvi.Search.SearchTweets(ISearchTweetsParameters searchTweetsParameters) at Book.ViewModels.Samples.Chapter02.Sample02.MainViewModel.<>c__DisplayClass46_0.<GetTweets>b__0() at System.Threading.Tasks.Task1.InnerInvoke()
at System.Threading.Tasks.Task.Execute()

I have pasted in the keys from twitter. Twitter says my access token has read and write access level.