Error "No such host" when connect mysql by service name

[zivfuture]

I am debugging my app in local dev machine with b2k.
this app running in default namespace. and it will connect mysql which in another namespace named "db",
connection string like this:
server=mysql.db.svc.cluster.local;port=3306;database=xxx;SslMode=None;uid=root;pwd=xxx;Allow User Variables=true

And i got this exception, but invoking another api works fine. only fail to access mysql by dns :

System.Net.Sockets.SocketException (11001): No such host is known
   at System.Net.NameResolutionPal.ProcessResult(SocketError errorCode, GetAddrInfoExContext* context)
    at System.Net.NameResolutionPal.GetAddressInfoExCallback(Int32 error, Int32 bytes, NativeOverlapped* overlapped)
    --- End of stack trace from previous location ---
      
    --- End of inner exception stack trace ---
        at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
        at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
        at System.Threading.Tasks.Task.Wait()
        at MySql.Data.Common.StreamCreator.GetTcpStream(MySqlConnectionStringBuilder settings, MyNetworkStream& networkStream)
        at MySql.Data.Common.StreamCreator.GetStream(MySqlConnectionStringBuilder settings, MyNetworkStream& networkStream)
        at MySql.Data.MySqlClient.NativeDriver.Open()
        at MySql.Data.MySqlClient.Driver.Open()
        at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
        at MySql.Data.MySqlClient.MySqlPool.CreateNewPooledConnection()
        at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
        at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
        at MySql.Data.MySqlClient.MySqlPool.GetConnection()
        at MySql.Data.MySqlClient.MySqlConnection.Open()
        at MySql.Data.MySqlClient.MySqlConnection.<OpenAsync>b__75_0()
        at System.Threading.Tasks.Task.InnerInvoke()
        at System.Threading.Tasks.Task.<>c.<.cctor>b__272_0(Object obj)
        at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
    --- End of stack trace from previous location ---
        at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
        at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
    --- End of stack trace from previous location ---
        at Dapper.SqlMapper.QueryAsync[T](IDbConnection cnn, Type effectiveType, CommandDefinition command) in /_/Dapper/SqlMapper.Async.cs:line 417
        at eBest.EventBus.MySql.MySqlEventStore.LoadToRetryAsync(CancellationToken cancellation) in D:\\Private\\GitHub\\eBest.FMCG\\src\\BuildBlocks\\eBest.EventBus.MySql\\MySqlEventStore.cs:line 75
        at eBest.EventBus.Dispatcher.Background.EnqueueBackgroundService.ExecuteAsync(CancellationToken stoppingToken) in D:\\Private\\GitHub\\eBest.FMCG\\src\\BuildBlocks\\eBest.EventBus.Dispatcher\\Background\\EnqueueBackgroundService.cs:line 33"}