The API you looked at cannot retrieve fundamental and reference fields. To retrieve these fields into a .NET application use either the .NET implementation of Eikon Data APIs or DEX2 library of legacy Eikon COM APIs.

Now I am getting

Could not load file or assembly 'EikonDataAPI, Version=2.0.4.3, Culture=neutral, PublicKeyToken=null' or one of its dependencies. An attempt was made to load a program with an incorrect format.

How can I figure out what maybe the problem? I don't see any missing references. I am using .NET Framework 4.6.1

packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
<package id="Deedle" version="1.2.5" targetFramework="net461" />
<package id="EikonDataAPI" version="0.4.3" targetFramework="net461" />
<package id="Microsoft.Extensions.DependencyInjection.Abstractions" version="2.0.0" targetFramework="net461" />
<package id="Microsoft.Extensions.Logging" version="2.0.1" targetFramework="net461" />
<package id="Microsoft.Extensions.Logging.Abstractions" version="2.0.1" targetFramework="net461" />
<package id="Microsoft.Extensions.Options" version="2.0.1" targetFramework="net461" />
<package id="Microsoft.Extensions.Primitives" version="2.0.0" targetFramework="net461" />
<package id="Newtonsoft.Json" version="11.0.1" targetFramework="net461" />
<package id="System.Runtime.CompilerServices.Unsafe" version="4.4.0" targetFramework="net461" />
</packages>

List of files under DEBUG directory:

06/06/2016 04:47 PM 2,011,648 Deedle.dll
06/06/2016 04:47 PM 1,971,712 Deedle.pdb
06/06/2016 04:47 PM 501,588 Deedle.xml
08/30/2019 08:42 AM 5,632 EikonAPITest.exe
08/30/2019 08:42 AM 18,072 EikonAPITest.exe.config
08/30/2019 08:42 AM 11,776 EikonAPITest.pdb
03/29/2018 08:57 AM 44,544 EikonDataAPI.dll
07/25/2017 12:48 AM 36,360 Microsoft.Extensions.DependencyInjection.Abstractions.dll
07/24/2017 04:30 PM 54,736 Microsoft.Extensions.DependencyInjection.Abstractions.xml
02/20/2018 09:41 PM 46,576 Microsoft.Extensions.Logging.Abstractions.dll
02/20/2018 12:14 PM 39,431 Microsoft.Extensions.Logging.Abstractions.xml
02/20/2018 09:41 PM 30,704 Microsoft.Extensions.Logging.dll
02/20/2018 12:14 PM 5,392 Microsoft.Extensions.Logging.xml
02/20/2018 09:41 PM 26,096 Microsoft.Extensions.Options.dll
02/20/2018 12:12 PM 27,433 Microsoft.Extensions.Options.xml
07/25/2017 12:48 AM 33,288 Microsoft.Extensions.Primitives.dll
07/24/2017 04:29 PM 31,759 Microsoft.Extensions.Primitives.xml
05/02/2018 08:46 AM 21,216 Microsoft.Win32.Primitives.dll
05/02/2018 08:46 AM 98,616 netstandard.dll
02/18/2018 10:44 AM 664,576 Newtonsoft.Json.dll
02/18/2018 10:44 AM 684,778 Newtonsoft.Json.xml
05/02/2018 08:46 AM 21,176 System.AppContext.dll
05/02/2018 08:46 AM 21,224 System.Collections.Concurrent.dll
05/02/2018 08:46 AM 21,696 System.Collections.dll
05/02/2018 08:46 AM 21,224 System.Collections.NonGeneric.dll
05/02/2018 08:46 AM 21,224 System.Collections.Specialized.dll
05/02/2018 08:46 AM 21,192 System.ComponentModel.dll
05/02/2018 08:46 AM 21,768 System.ComponentModel.EventBasedAsync.dll
05/02/2018 08:46 AM 21,752 System.ComponentModel.Primitives.dll
05/02/2018 08:46 AM 22,784 System.ComponentModel.TypeConverter.dll
05/02/2018 08:46 AM 21,160 System.Console.dll
05/02/2018 08:46 AM 154,448 System.Data.Common.dll
05/02/2018 08:46 AM 21,736 System.Diagnostics.Contracts.dll
05/02/2018 08:46 AM 21,208 System.Diagnostics.Debug.dll
05/02/2018 08:46 AM 21,248 System.Diagnostics.FileVersionInfo.dll
05/02/2018 08:46 AM 21,728 System.Diagnostics.Process.dll
05/02/2018 08:46 AM 23,936 System.Diagnostics.StackTrace.dll
05/02/2018 08:46 AM 21,280 System.Diagnostics.TextWriterTraceListener.dll
05/02/2018 08:46 AM 21,208 System.Diagnostics.Tools.dll
05/02/2018 08:46 AM 21,744 System.Diagnostics.TraceSource.dll
05/02/2018 08:46 AM 31,608 System.Diagnostics.Tracing.dll
05/02/2018 08:46 AM 21,208 System.Drawing.Primitives.dll
05/02/2018 08:46 AM 22,224 System.Dynamic.Runtime.dll
05/02/2018 08:46 AM 21,744 System.Globalization.Calendars.dll
05/02/2018 08:46 AM 21,192 System.Globalization.dll
05/02/2018 08:46 AM 25,992 System.Globalization.Extensions.dll
05/02/2018 08:46 AM 110,944 System.IO.Compression.dll
05/02/2018 08:46 AM 21,224 System.IO.Compression.ZipFile.dll
05/02/2018 08:46 AM 21,144 System.IO.dll
05/02/2018 08:46 AM 21,192 System.IO.FileSystem.dll
05/02/2018 08:46 AM 21,232 System.IO.FileSystem.DriveInfo.dll
05/02/2018 08:46 AM 21,232 System.IO.FileSystem.Primitives.dll
05/02/2018 08:46 AM 21,224 System.IO.FileSystem.Watcher.dll
05/02/2018 08:46 AM 21,208 System.IO.IsolatedStorage.dll
05/02/2018 08:46 AM 21,216 System.IO.MemoryMappedFiles.dll
05/02/2018 08:46 AM 21,168 System.IO.Pipes.dll
05/02/2018 08:46 AM 21,232 System.IO.UnmanagedMemoryStream.dll
05/02/2018 08:46 AM 21,152 System.Linq.dll
05/02/2018 08:46 AM 22,224 System.Linq.Expressions.dll
05/02/2018 08:46 AM 21,192 System.Linq.Parallel.dll
05/02/2018 08:46 AM 21,192 System.Linq.Queryable.dll
05/02/2018 08:46 AM 198,472 System.Net.Http.dll
05/02/2018 08:46 AM 21,208 System.Net.NameResolution.dll
05/02/2018 08:46 AM 22,248 System.Net.NetworkInformation.dll
05/02/2018 08:46 AM 21,168 System.Net.Ping.dll
05/02/2018 08:46 AM 22,216 System.Net.Primitives.dll
05/02/2018 08:46 AM 21,184 System.Net.Requests.dll
05/02/2018 08:46 AM 21,696 System.Net.Security.dll
05/02/2018 08:46 AM 30,544 System.Net.Sockets.dll
05/02/2018 08:46 AM 21,232 System.Net.WebHeaderCollection.dll
05/02/2018 08:46 AM 21,224 System.Net.WebSockets.Client.dll
05/02/2018 08:46 AM 21,192 System.Net.WebSockets.dll
05/02/2018 08:46 AM 21,696 System.ObjectModel.dll
05/02/2018 08:46 AM 22,200 System.Reflection.dll
05/02/2018 08:46 AM 21,224 System.Reflection.Extensions.dll
05/02/2018 08:46 AM 21,736 System.Reflection.Primitives.dll
05/02/2018 08:46 AM 21,200 System.Resources.Reader.dll
05/02/2018 08:46 AM 21,232 System.Resources.ResourceManager.dll
05/02/2018 08:46 AM 21,200 System.Resources.Writer.dll
07/19/2017 10:01 AM 21,944 System.Runtime.CompilerServices.Unsafe.dll
07/19/2017 10:01 AM 7,044 System.Runtime.CompilerServices.Unsafe.xml
05/02/2018 08:46 AM 21,784 System.Runtime.CompilerServices.VisualC.dll
05/02/2018 08:46 AM 29,360 System.Runtime.dll
05/02/2018 08:46 AM 21,720 System.Runtime.Extensions.dll
05/02/2018 08:46 AM 21,200 System.Runtime.Handles.dll
05/02/2018 08:46 AM 24,296 System.Runtime.InteropServices.dll
05/02/2018 08:46 AM 28,624 System.Runtime.InteropServices.RuntimeInformation.dll
05/02/2018 08:46 AM 21,200 System.Runtime.Numerics.dll
05/02/2018 08:46 AM 21,264 System.Runtime.Serialization.Formatters.dll
05/02/2018 08:46 AM 21,240 System.Runtime.Serialization.Json.dll
05/02/2018 08:46 AM 27,048 System.Runtime.Serialization.Primitives.dll
05/02/2018 08:46 AM 24,816 System.Runtime.Serialization.Xml.dll
05/02/2018 08:46 AM 21,200 System.Security.Claims.dll
05/02/2018 08:46 AM 47,016 System.Security.Cryptography.Algorithms.dll
05/02/2018 08:46 AM 21,240 System.Security.Cryptography.Csp.dll
05/02/2018 08:46 AM 21,256 System.Security.Cryptography.Encoding.dll
05/02/2018 08:46 AM 21,784 System.Security.Cryptography.Primitives.dll
05/02/2018 08:46 AM 22,832 System.Security.Cryptography.X509Certificates.dll
05/02/2018 08:46 AM 21,208 System.Security.Principal.dll
05/02/2018 08:46 AM 22,392 System.Security.SecureString.dll
05/02/2018 08:46 AM 21,696 System.Text.Encoding.dll
05/02/2018 08:46 AM 21,232 System.Text.Encoding.Extensions.dll
05/02/2018 08:46 AM 21,232 System.Text.RegularExpressions.dll
05/02/2018 08:46 AM 22,192 System.Threading.dll
05/02/2018 08:46 AM 37,752 System.Threading.Overlapped.dll
05/02/2018 08:46 AM 22,224 System.Threading.Tasks.dll
05/02/2018 08:46 AM 21,232 System.Threading.Tasks.Parallel.dll
05/02/2018 08:46 AM 21,200 System.Threading.Thread.dll
05/02/2018 08:46 AM 21,216 System.Threading.ThreadPool.dll
05/02/2018 08:46 AM 21,200 System.Threading.Timer.dll
05/02/2018 08:46 AM 79,176 System.ValueTuple.dll
05/02/2018 08:46 AM 21,712 System.Xml.ReaderWriter.dll
05/02/2018 08:46 AM 21,696 System.Xml.XDocument.dll
05/02/2018 08:46 AM 21,712 System.Xml.XmlDocument.dll
05/02/2018 08:46 AM 21,712 System.Xml.XmlSerializer.dll
05/02/2018 08:46 AM 21,176 System.Xml.XPath.dll
05/02/2018 08:46 AM 22,904 System.Xml.XPath.XDocument.dll

Figured out the answer. I needed to se project to x64 from ANY

Thank you