Unable to connect to Oracle database from Azure Function in VS Code

I am trying to connect to an on-premises Oracle database from an Azure Function using Visual Studio Code. I have installed the necessary packages (Oracle.ManagedDataAccess, System.Configuration.ConfigurationManager, System.Security.Permissions) and configured my connection string as follows:

Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=XYZ)(PORT=1648))(CONNECT_DATA=(SERVICE_NAME=XYZ)));User ID=xyz;Password=XYZ;

However, I am encountering a connection timeout error (ORA-50000: Connection request timed out). I have verified that the host is up and running, and I can connect to the database using the Oracle SQL Developer extension in VS Code.

Code :

using Microsoft.AspNetCore.Http;

using Microsoft.AspNetCore.Mvc;

using Microsoft.Azure.Functions.Worker;

using Microsoft.Extensions.Logging;

using Oracle.ManagedDataAccess.Client;

using System.Data;

namespace Company.Function

{

public class HttpTrigger1

{

    private readonly ILogger<HttpTrigger1> _logger;

    public HttpTrigger1(ILogger<HttpTrigger1> logger)

    {

        _logger = logger;

    }

    [Function("HttpTrigger1")]

    public IActionResult Run([HttpTrigger(AuthorizationLevel.Function, "get", "post")] HttpRequest req)

    {

        _logger.LogInformation("C# HTTP trigger function processed a request.");

        string connectionString = "Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=XYZ)(PORT=1648))(CONNECT_DATA=(SERVICE_NAME=XYZ)));User Id=XYZ;Password=XYZ;Validate Connection=true;";

        using (var conn = new OracleConnection(connectionString))

        {

            try

            {

                conn.Open();

                _logger.LogInformation("Connected to Oracle database.");

                using (var cmd = new OracleCommand("SELECT * FROM dual", conn))

                {

                    using (var reader = cmd.ExecuteReader())

                    {

                        while (reader.Read())

                        {

                            string result = reader.GetString(0);

                            _logger.LogInformation($"Query Result: {result}");

                        }

                    }

                }

            }

            catch (Exception ex)

            {

                _logger.LogError($"Error connecting to Oracle database: {ex.Message}");

                return new StatusCodeResult(StatusCodes.Status500InternalServerError);

            }

        }

        return new OkObjectResult("Oracle database query executed successfully.");

    }

}

}

Could you please help me troubleshoot this issue?