After launching game on Windows x32 the script working with MySQL database could not be instantiated

In the Unity Editor everything works fine. Fail comes during launch the build after choosing a resolution and clicking "Play".

When I remove MySql* variables everything is ok also. What should I do to let this script work?

Script:

 using UnityEngine;
 using MySql.Data.MySqlClient;
 using System;
 
 public class MySQLManager : MonoBehaviour {
     
     MySqlConnection loginConnection = null;
     MySqlCommand queryCommand = null;
     MySqlDataReader reader = null;
     ...
 }

output_log:

     Initialize engine version: 4.5.0f6 (fd4616464986)
 GfxDevice: creating device client; threaded=1
 Direct3D:
     Version:  Direct3D 9.0c [igdumd32.dll 9.17.10.3190]
     Renderer: Intel(R) HD Graphics
     Vendor:   Intel
     VRAM:     944 MB (via DXGI)
     Caps:     Shader=30 DepthRT=1 NativeDepth=1 NativeShadow=1 DF16=1 INTZ=1 RAWZ=0 NULL=1 RESZ=1 SlowINTZ=0
 Begin MonoManager ReloadAssembly
 Platform assembly: D:\server\server_Data\Managed\UnityEngine.dll (this message is harmless)
 Loading D:\server\server_Data\Managed\UnityEngine.dll into Unity Child Domain
 Platform assembly: D:\server\server_Data\Managed\Assembly-CSharp.dll (this message is harmless)
 Loading D:\server\server_Data\Managed\Assembly-CSharp.dll into Unity Child Domain
 Platform assembly: D:\server\server_Data\Managed\MySql.Data.dll (this message is harmless)

 - Completed reload, in  0.254 seconds
 desktop: 1366x768 60Hz; virtual: 1366x768 at 0,0
 <RI> Initializing input.
 
 <RI> Input initialized.

I select the resolution and clicked "Play!"

 Platform assembly: D:\server\server_Data\Managed\System.dll (this message is harmless)
 Platform assembly: D:\server\server_Data\Managed\System.Core.dll (this message is harmless)

 The script behaviour 'MySQLManager' could not be instantiated!
  
 (Filename:  Line: 1657)
 
 Platform assembly: D:\server\server_Data\Managed\System.Configuration.dll (this message is harmless)
 Platform assembly: D:\server\server_Data\Managed\System.Xml.dll (this message is harmless)
 Server successfully started on port 7100
  
 (Filename: C:/BuildAgent/work/aeedb04a1292f85a/artifacts/Stand

 alonePlayerGenerated/UnityEngineDebug.cpp Line: 49)