Issue All websites stopped sending emails with error "No such host is known"

[jose12]

Server operating system version

windows server 2019

Plesk version and microupdate number

18.0.55

Hi Suddenly all my websites stop sending emails yesterday night.

They are from different providers and using different smtp servers so it should be something with the server or plesk. We did several tests with no success .
Do you have any ideas?

The error is "No such host is known" and it is happening in all domains
Any upgrade yesterday? Plesk 18.0.55


Log level Error Short message A tarefa agendada "Send emails" falhou com o erro "No such host is known. (www.domain.net:443)" (Tipo de tarefa: "Nop.Services.Messages.QueuedMessagesSendTask, Nop.Services". Nome da loja: "Store". Endereço de execução da tarefa: "https://domain.net/scheduletask/runtask").

Full message System.Net.Http.HttpRequestException: No such host is known. (www.[redacted].net:443) ---> System.Net.Sockets.SocketException (11001): No such host is known. at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken) at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource.GetResult(Int16 token) at System.Net.Sockets.Socket.g__WaitForConnectWithCancellation|277_0(AwaitableSocketAsyncEventArgs saea, ValueTask connectTask, CancellationToken cancellationToken) at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken) --- End of inner exception stack trace --- at System.Net.Http.HttpConnectionPool.ConnectToTcpHostAsync(String host, Int32 port, HttpRequestMessage initialRequest, Boolean async, CancellationToken cancellationToken) at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken) at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken) at System.Net.Http.HttpConnectionPool.AddHttp11ConnectionAsync(HttpRequestMessage request) at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(CancellationToken cancellationToken) at System.Net.Http.HttpConnectionPool.GetHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken) at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken) at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken) at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) at System.Net.Http.HttpClient.g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken) at Nop.Services.ScheduleTasks.TaskScheduler.TaskThread.RunAsync() in C:\andrei\nop_sources\src\Libraries\Nop.Services\ScheduleTasks\TaskScheduler.cs:line 216