ReadHelperException: returned 0 on editor

[SaulNunez]

I have two instances of a project via Project Cloner I wish to connect. In the host, there are no errors. On the client I want to connect, several errors are thrown at once.

Not Connected
UnityEngine.Debug:LogError(Object)
Mirror.SimpleWeb.SimpleWebTransport:ClientSend(Int32, ArraySegment`1) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:188)
Mirror.NetworkConnectionToServer:Send(ArraySegment`1, Int32) (at Assets/Mirror/Runtime/NetworkConnectionToServer.cs:19)
Mirror.NetworkConnection:Send(NetworkPingMessage, Int32) (at Assets/Mirror/Runtime/NetworkConnection.cs:123)
Mirror.NetworkClient:Send(NetworkPingMessage, Int32) (at Assets/Mirror/Runtime/NetworkClient.cs:238)
Mirror.NetworkTime:UpdateClient() (at Assets/Mirror/Runtime/NetworkTime.cs:61)
Mirror.NetworkClient:OnConnected() (at Assets/Mirror/Runtime/NetworkClient.cs:189)
Mirror.SimpleWeb.SimpleWebClient:ProcessMessageQueue(MonoBehaviour) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/Client/SimpleWebClient.cs:66)
Mirror.SimpleWeb.SimpleWebTransport:ProcessMessages() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:128)
Mirror.SimpleWeb.SimpleWebTransport:LateUpdate() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:117)

Not Connected
UnityEngine.Debug:LogError(Object)
Mirror.SimpleWeb.SimpleWebTransport:ClientSend(Int32, ArraySegment`1) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:188)
Mirror.NetworkConnectionToServer:Send(ArraySegment`1, Int32) (at Assets/Mirror/Runtime/NetworkConnectionToServer.cs:19)
Mirror.NetworkConnection:Send(ReadyMessage, Int32) (at Assets/Mirror/Runtime/NetworkConnection.cs:123)
Mirror.ClientScene:Ready(NetworkConnection) (at Assets/Mirror/Runtime/ClientScene.cs:180)
Mirror.NetworkManager:OnClientConnect(NetworkConnection) (at Assets/Mirror/Runtime/NetworkManager.cs:1392)
Mirror.NetworkRoomManager:OnClientConnect(NetworkConnection) (at Assets/Mirror/Components/NetworkRoomManager.cs:473)
Mirror.NetworkManager:OnClientAuthenticated(NetworkConnection) (at Assets/Mirror/Runtime/NetworkManager.cs:1261)
Mirror.NetworkManager:OnClientConnectInternal(NetworkConnection, ConnectMessage) (at Assets/Mirror/Runtime/NetworkManager.cs:1245)
Mirror.<>c__DisplayClass6_0`2:<WrapHandler>b__0(NetworkConnection, NetworkReader, Int32) (at Assets/Mirror/Runtime/MessagePacker.cs:120)
Mirror.NetworkConnection:InvokeHandler(Int32, NetworkReader, Int32) (at Assets/Mirror/Runtime/NetworkConnection.cs:192)
Mirror.NetworkConnection:InvokeHandler(ConnectMessage, Int32) (at Assets/Mirror/Runtime/NetworkConnection.cs:220)
Mirror.NetworkClient:OnConnected() (at Assets/Mirror/Runtime/NetworkClient.cs:190)
Mirror.SimpleWeb.SimpleWebClient:ProcessMessageQueue(MonoBehaviour) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/Client/SimpleWebClient.cs:66)
Mirror.SimpleWeb.SimpleWebTransport:ProcessMessages() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:128)
Mirror.SimpleWeb.SimpleWebTransport:LateUpdate() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:117)

Not Connected
UnityEngine.Debug:LogError(Object)
Mirror.SimpleWeb.SimpleWebTransport:ClientSend(Int32, ArraySegment`1) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:188)
Mirror.NetworkConnectionToServer:Send(ArraySegment`1, Int32) (at Assets/Mirror/Runtime/NetworkConnectionToServer.cs:19)
Mirror.NetworkConnection:Send(AddPlayerMessage, Int32) (at Assets/Mirror/Runtime/NetworkConnection.cs:123)
Mirror.ClientScene:AddPlayer(NetworkConnection) (at Assets/Mirror/Runtime/ClientScene.cs:151)
Mirror.NetworkManager:OnClientConnect(NetworkConnection) (at Assets/Mirror/Runtime/NetworkManager.cs:1395)
Mirror.NetworkRoomManager:OnClientConnect(NetworkConnection) (at Assets/Mirror/Components/NetworkRoomManager.cs:473)
Mirror.NetworkManager:OnClientAuthenticated(NetworkConnection) (at Assets/Mirror/Runtime/NetworkManager.cs:1261)
Mirror.NetworkManager:OnClientConnectInternal(NetworkConnection, ConnectMessage) (at Assets/Mirror/Runtime/NetworkManager.cs:1245)
Mirror.<>c__DisplayClass6_0`2:<WrapHandler>b__0(NetworkConnection, NetworkReader, Int32) (at Assets/Mirror/Runtime/MessagePacker.cs:120)
Mirror.NetworkConnection:InvokeHandler(Int32, NetworkReader, Int32) (at Assets/Mirror/Runtime/NetworkConnection.cs:192)
Mirror.NetworkConnection:InvokeHandler(ConnectMessage, Int32) (at Assets/Mirror/Runtime/NetworkConnection.cs:220)
Mirror.NetworkClient:OnConnected() (at Assets/Mirror/Runtime/NetworkClient.cs:190)
Mirror.SimpleWeb.SimpleWebClient:ProcessMessageQueue(MonoBehaviour) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/Client/SimpleWebClient.cs:66)
Mirror.SimpleWeb.SimpleWebTransport:ProcessMessages() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:128)
Mirror.SimpleWeb.SimpleWebTransport:LateUpdate() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:117)

ReadHelperException: returned 0
Mirror.SimpleWeb.ReadHelper.Read (System.IO.Stream stream, System.Byte[] outBuffer, System.Int32 outOffset, System.Int32 length) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/Common/ReadHelper.cs:24)
Mirror.SimpleWeb.ReceiveLoop.ReadOneMessage (Mirror.SimpleWeb.ReceiveLoop+Config config, System.Byte[] buffer) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/Common/ReceiveLoop.cs:113)
Mirror.SimpleWeb.ReceiveLoop.Loop (Mirror.SimpleWeb.ReceiveLoop+Config config) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/Common/ReceiveLoop.cs:64)
UnityEngine.Logger:LogException(Exception)
Mirror.NetworkClient:OnError(Exception) (at Assets/Mirror/Runtime/NetworkClient.cs:158)
Mirror.SimpleWeb.SimpleWebTransport:<ClientConnect>b__34_2(Exception) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:171)
Mirror.SimpleWeb.SimpleWebClient:ProcessMessageQueue(MonoBehaviour) (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/Client/SimpleWebClient.cs:76)
Mirror.SimpleWeb.SimpleWebTransport:ProcessMessages() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:128)
Mirror.SimpleWeb.SimpleWebTransport:LateUpdate() (at Assets/Mirror/Runtime/Transport/SimpleWebTransport/SimpleWebTransport.cs:117)

Running Windows with Unity 2019.4.8f1

NetworkRoomManager

SimpleWebTransport

[James-Frowen]

ReadHelperException: returned 0 errors just means the connection was closed. By itself it isnt a problem.

I need to improve the logging for this so that it is easier to understand what is happening.