ORA-12154 : TNS : 지정된 연결 식별자를 확인할 수없고 ORA-06413 : 연결이 열리지 않습니다

Can you try the below

1. Include Oracle.ManagedDataAccess.dll in your solution.
2. In web.config, Under Configuration and connectionstrings, include the below

    <oracle.manageddataaccess.client>
        <version number="*">
          <dataSources>
            <dataSource alias="UATDB" descriptor="(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = ORACLEDBIP)(PORT = PORT))(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = ORACLE)))"/>
        </dataSources>
        </version>
      </oracle.manageddataaccess.client>

        <connectionStrings>
        <add name="UATCONNECTIONSTRING" connectionString="Data Source=UATDB;User Id=username;Password=password;Min Pool Size=10; Connection Lifetime=300;Connection Timeout=300;Incr Pool Size=5;Decr Pool Size=2;" providerName="Oracle.DataAccess.Client"/>  
      </connectionStrings>


3. Refer the dll in your application

    using Oracle.ManagedDataAccess;

    using (OracleConnection oraConn = new OracleConnection(strOracleConn))
    {
        oraConn.Open();
        OracleCommand oraCommand = new OracleCommand();
        oraCommand.CommandType = System.Data.CommandType.StoredProcedure;
        oraCommand.CommandText = "sp name";
        oraCommand.Connection = oraConn;
    }



Web.config file

<?xml version="1.0"?>
<configuration>
  <configSections>
    <section name="oracle.manageddataaccess.client" type="OracleInternal.Common.ODPMSectionHandler, Oracle.ManagedDataAccess"/>
  </configSections>
  <oracle.manageddataaccess.client>
    <version number="*">
      <dataSources>
        <dataSource alias="UATDB" descriptor="(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = IP)(PORT = PORT))(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = ORACLE)))"/>
      </dataSources>
    </version>
  </oracle.manageddataaccess.client>
  <system.web>
    <compilation debug="true" targetFramework="4.6.1"/>
    <customErrors mode="Off"/>
    <httpRuntime executionTimeout="600"/>
    <authentication mode="Windows"/>
    <authorization>
      <deny users="?"/>
    </authorization>
    <pages controlRenderingCompatibilityVersion="4.0">
      <namespaces>
        <add namespace="System.Web.Optimization"/>
      </namespaces>
      <controls>
        <add assembly="Microsoft.AspNet.Web.Optimization.WebForms" namespace="Microsoft.AspNet.Web.Optimization.WebForms" tagPrefix="webopt"/>
      </controls>
    </pages>
    <httpModules>
      <add name="ApplicationInsightsWebTracking" type="Microsoft.ApplicationInsights.Web.ApplicationInsightsHttpModule, Microsoft.AI.Web"/>
    </httpModules>
  </system.web>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed"/>
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" culture="neutral" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, 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=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+"/>
    </compilers>
  </system.codedom>
  <connectionStrings>
    <add name="UATCONNECTIONSTRING" connectionString="Data Source=UATDB;User Id=user1;Password=pass12;Min Pool Size=10; Connection Lifetime=300;Connection Timeout=300;Incr Pool Size=5;Decr Pool Size=2;" providerName="Oracle.DataAccess.Client"/>
  </connectionStrings>
  <appSettings>
  </appSettings>
  <system.webServer>
    <validation validateIntegratedModeConfiguration="false"/>
    <modules>
      <remove name="ApplicationInsightsWebTracking"/>
      <add name="ApplicationInsightsWebTracking" type="Microsoft.ApplicationInsights.Web.ApplicationInsightsHttpModule, Microsoft.AI.Web" preCondition="managedHandler"/>
    </modules>
  </system.webServer>
    <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
      <file type="log4net.Util.PatternString">
        <conversionPattern value="../Logs/RunningLog/WrapperRunningLog-" />
      </file>
      <rollingStyle value="Date" />
      <datePattern value="yyyyMMddHH.lo\g" />
      <staticLogFileName value="false" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date %level - %message%newline" />
      </layout>
    </appender>
    <appender name="RollingLogFileAppenderUpdateStatus" type="log4net.Appender.RollingFileAppender">
      <file type="log4net.Util.PatternString">
        <conversionPattern value="../Logs/UpdateStatusLog/StatusLog-" />
      </file>
      <rollingStyle value="Date" />
      <datePattern value="yyyyMMdd.log" />
      <staticLogFileName value="false" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date %level - %message%newline" />
      </layout>
    </appender>
    <root>
      <level value="ALL" />
    </root>
    <logger name="RunningLog">
      <level value="ALL" />
      <appender-ref ref="RollingLogFileAppender"   />
    </logger>
    <logger name="UpdateStatusLog">
      <level value="ALL" />
      <appender-ref ref="RollingLogFileAppenderUpdateStatus" />
      <appender-ref ref="RollingLogFileAppender"   />
    </logger>
  </log4net>
</configuration>