Active Directory synchronization failed - Error [Th 14] Active Directory synchronization failed.

This is the result when I try to syncronize:

Error [Th 14] Active Directory synchronization failed. Reason: System.Net.Http.HttpRequestException: Error al enviar la solicitud. ---> System.Net.WebException: Se ha terminado la conexión: Error inesperado de envío. ---> System.IO.IOException: No se puede escribir datos de en la conexión de transporte: Se ha forzado la interrupción de una conexión existente por el host remoto. ---> System.Net.Sockets.SocketException: Se ha forzado la interrupción de una conexión existente por el host remoto
en System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)
en System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
--- Fin del seguimiento de la pila de la excepción interna ---
en System.Net.TlsStream.EndWrite(IAsyncResult asyncResult)
en System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)
--- Fin del seguimiento de la pila de la excepción interna ---
en System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
en System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)
--- Fin del seguimiento de la pila de la excepción interna ---
en CommandLib.HttpRequestCommand.SyncExeImpl(Object runtimeArg)
en CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
en CommandLib.RetryableCommand.SyncExeImpl(Object runtimeArg)
en CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
en SophosADSync.SophosCloudWebClient.MakeRequest(String address, HttpMethod method, Byte[] data, Dictionary`2 headers, Int32 maxRetries, Command context, List`1 doNotCallRetryStatusCodeList)
en SophosADSync.SophosCloudWebClient.SubmitPreviewSyncData(SyncSessionPayload payload, Command context)
en SophosADSync.SophosCloudAPI.SubmitPreviewSyncDataV5(LDAPData ldapData, String clientUid, String rootDomainNamingContext, Command context)
en SophosADSync.ADSyncCommand.PreviewSync(LDAPData ldapData, Boolean isManualSync, ForestConfigV2Get forestConfig)
en SophosADSync.ADSyncCommand.SyncExeImpl(Object runtimeArg)
en CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
en SophosADSync.ChangeStateAndADSyncCommand.SyncExeImpl(Object runtimeArg)
09:41:27.937 Error [Th 14] Context for failure: RecurringCommand=>ScheduledCommand=>ChangeStateAndADSyncCommand=>ADSyncCommand=>RetryableCommand=>HttpRequestCommand(1587)

Any idea why is the root cause for this issue and how can I solve It?