the first one in case of '"', second is '\'
{"Message":"After parsing a value an unexpected character was encountered: \". Line 1, position 41.","StackTrace":" at Newtonsoft.Json.JsonTextReader.ParsePostValue(Char currentChar)\r\n at Newtonsoft.Json.JsonTextReader.Read()\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateDictionary(IWrappedDictionary dictionary, JsonReader reader, JsonDictionaryContract contract, String id)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateAndPopulateDictionary(JsonReader reader, JsonDictionaryContract contract, String id)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueNonProperty(JsonReader reader, Type objectType, JsonContract contract)\r\n at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)\r\n at Ext.Net.JSON.Deserialize(String value, Type type, List`1 converters, IContractResolver resolver)\r\n at Ext.Net.JSON.Deserialize[T](String value)\r\n at WServices.GenericService.LoadGridData(Int32 start, Int32 limit, String dbTableName, String dataColumns, Int32 pageSize, String filters) in E:\\work\\Prj\\Services\\GenericService.asmx.cs:line 467","ExceptionType":"Newtonsoft.Json.JsonReaderException"}
*******************
{"Message":"After parsing a value an unexpected character was encountered: u. Line 1, position 44.","StackTrace":" at Newtonsoft.Json.JsonTextReader.ParsePostValue(Char currentChar)\r\n at Newtonsoft.Json.JsonTextReader.Read()\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateDictionary(IWrappedDictionary dictionary, JsonReader reader, JsonDictionaryContract contract, String id)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateAndPopulateDictionary(JsonReader reader, JsonDictionaryContract contract, String id)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue)\r\n at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueNonProperty(JsonReader reader, Type objectType, JsonContract contract)\r\n at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)\r\n at Ext.Net.JSON.Deserialize(String value, Type type, List`1 converters, IContractResolver resolver)\r\n at Ext.Net.JSON.Deserialize[T](String value)\r\n at Services.GenericService.LoadGridData(Int32 start, Int32 limit, String dbTableName, String dataColumns, Int32 pageSize, String filters) in E:\\work\\Prj\\Services\\GenericService.asmx.cs:line 467","ExceptionType":"Newtonsoft.Json.JsonReaderException"}