I am working on an API in .NET using Net Framework 4.7.2 which is compatible with Oracle.ManagedDataAccess, I already have everything done, controllers, models and the respective classes that run using the controllers in their call.

The problem I have is that when testing in postman I get an error message:

[{“Error”: “1”, “Message”: “An exception occurred in the ‘OracleInternal.Common.ProviderConfig’ type initializer.”}]

This error comes from the exception of:

public static List<MensajeCursor> AccesoUsuario (UserLogin request)
{
    List<MensajeCursor> Cursor = new List<MensajeCursor>();
    try
    {
       cmd = new OracleCommand();
        cmd.Connection = Conection.getConnection();
        cmd.CommandText = "MYQUERY";
        cmd.CommandType = CommandType.Text;
        cmd.Parameters.Add("result", OracleDbType.RefCursor).Direction = ParameterDirection.ReturnValue;
        cmd.Parameters.Add("p_User", OracleDbType.Varchar2).Value = request.User;
        cmd.Parameters.Add("p_Pass", OracleDbType.Varchar2).Value = request.Pass;
        cmd.Parameters.Add("p_App", OracleDbType.Int32, int.MaxValue).Value = appNumber;

        reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            Cursor.Add(new MensajeCursor()
            {
            Error = reader[0] == DBNull.Value ? "" : reader.GetString(0),
            Message = reader[1] == DBNull.Value ? "" : reader.GetString(1)
            });
        }
        reader.Close();
        reader.Dispose();
        cmd.Dispose();
        cmd.Connection.Close();
    } catch (Exception ex) {
        Cursor.Add(new MensajeCursor()
        {
            Error = "1",
            Message = ex.Message // Returned Error
        });
    }
    return Cursor;
}

Is there any way to know why it happens?

This is my list of packages used (without problems with the version and compatibility):
Packages List Image

This is my web.config:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <system.web>
        <compilation targetFramework="4.7.2" />
        <httpRuntime targetFramework="4.7.2"  maxRequestLength="102400"/> <!-- 100 MB Aprox -->
    </system.web>
    <system.webServer>
        <handlers>
            <!-- <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
            <remove name="OPTIONSVerbHandler" />
            <remove name="TRACEVerbHandler" /> 
            <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />-->
        </handlers>
        <defaultDocument>
            <files>
                <clear />
                <add value="Login.html" />
            </files>
        </defaultDocument>
        <httpErrors errorMode="DetailedLocalOnly" />
        <security>
            <requestFiltering>
                <requestLimits maxAllowedContentLength="100000000" /> <!-- 100 MB -->
            </requestFiltering>
        </security>
    </system.webServer>
    <runtime>
        <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
            <dependentAssembly>
                <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
                <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
            </dependentAssembly>
            <dependentAssembly>
                <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
                <bindingRedirect oldVersion="1.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
            </dependentAssembly>
            <dependentAssembly>
                <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
                <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
            </dependentAssembly>
            <dependentAssembly>
                <publisherPolicy apply="no" />
                <assemblyIdentity name="Oracle.ManagedDataAccess" publicKeyToken="89b483f429c47342" culture="neutral" />
            </dependentAssembly>
        </assemblyBinding>
    </runtime>
    <system.codedom>
        <compilers>
            <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
            <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE="Web" /optionInfer+" />
        </compilers>
    </system.codedom>
    <system.data>
        <DbProviderFactories>
            <remove invariant="Oracle.ManagedDataAccess.Client" />
            <add name="ODP.NET, Managed Driver" invariant="Oracle.ManagedDataAccess.Client" description="Oracle Data Provider for .NET, Managed Driver" type="Oracle.ManagedDataAccess.Client.OracleClientFactory, Oracle.ManagedDataAccess, Version=4.122.23.1, Culture=neutral, PublicKeyToken=89b483f429c47342" />
        </DbProviderFactories>
    </system.data>
    <connectionStrings>
        <add name="DB_CONN" connectionString="MY DATA SOURCE"/>
    </connectionStrings>
</configuration>

If you need additional info let me know.