Issues after upgrade - unable to communicate with front-end server

Issues after upgrade - unable to communicate with front-end server

We have 2 servers in environment - one is front-end + DC (serverA), another is front-end only (serverB). We have recently acquired serverB and installed platform server revision, while the serverA was still on

At the installation time everything went rather smooth and we didn't see any issues.

I have just upgraded serverA to and while republishing components (an upgrade step from checklist) I started getting issues while communication with serverB (see error below). I have checked the configuration tool and it is pointing properly to serverA, I can successfully ping serverA from serverB by the name and IP address, so one is visible from another.

Additionally, the serverB is extremely slow as it seems to be trying to contact serverA for license and is failing to do so. Again - I can ping serverA (which is DC in this configuration) just fine from serverB.

This looks like serverB has lost the connection and/or license, but I don't see how I can re-establish the connection and restore the licence on it.

Publishing Error: Error broadcasting message to Front-end Server serverB (XX.XX.XX.XX)):System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it XX.XX.XX.XX:12001

Server stack trace:
   at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
   at System.Runtime.Remoting.Channels.RemoteConnection.CreateNewSocket(EndPoint ipEndPoint)
   at System.Runtime.Remoting.Channels.RemoteConnection.CreateNewSocket()
   at System.Runtime.Remoting.Channels.SocketCache.GetSocket(String machinePortAndSid, Boolean openNew)
   at System.Runtime.Remoting.Channels.Tcp.TcpClientTransportSink.SendRequestWithRetry(IMessage msg, ITransportHeaders requestHeaders, Stream requestStream)
   at System.Runtime.Remoting.Channels.Tcp.TcpClientTransportSink.ProcessMessage(IMessage msg, ITransportHeaders requestHeaders, Stream requestStream, ITransportHeaders& responseHeaders, Stream& responseStream)
   at System.Runtime.Remoting.Channels.BinaryClientFormatterSink.SyncProcessMessage(IMessage msg)

Exception rethrown at [0]:
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
   at OutSystems.HubEdition.IBroadcastListener.MessageTransmission(BroadcastMessage msg)
   at #iVe.#lHb.#VYe(BroadcastMessage msg, Dictionary`2 serversTable, HEMessageArrayList messages, String nodeName, String ipAddress, Boolean useCompactMsg, #JVe countdown, #s6e serviceKind).
Hello Vlad,

You should reach out to OutSystems support...
Did you install serverB in a farm configuration, i.e., did you follow up the installation checklist configured to install a farm instead of a standalone installation?