Problem about transmission channel in omnet++ in a vanet project

Question

I am new to omnet++ version 5.6.2 and I am simulating a project on VANETS unsing veins 5.0 framework, however, when executing the sumulation, an error appears. Like getTransmission channel(): No transmission channel found in the connection path. As you can see in the picture. However here is my code for the modules named in the error. Please help me to solve this problem enter image description here

The Router.ned file

package org.car2x.veins.modules.EdgeComputing;

import org.car2x.veins.base.modules.*;

import org.car2x.veins.modules.nic.Nic80211p;

import org.car2x.veins.modules.EdgeComputing.*;

import org.car2x.veins.modules.EdgeComputing.connectedApplications.*;

simple Router
{
    parameters:
        @display("i=device/accesspoint");
    gates:
        inout gate[];
}

The EdgeApplConn.ned

        package org.car2x.veins.modules.EdgeComputing.connectedApplications;
import org.car2x.veins.modules.application.ieee80211p.DemoBaseApplLayer;

simple EdgeApplConn extends DemoBaseApplLayer
{
    parameters:
        @class(veins::EdgeApplConn);
        double x;
        double y;
        double z;
// There are 2 scheduling modes:  SWPT-based (true) and FCFS-based (false)
        bool schedSWPT = default(true);
        @display("i=block/app2");
    //  double broadcastInterval @unit("s")=default(1s);
    //  bool TCPMATLAB=default(false);
    gates:
        inout ControlEthgPort;
        inout DataEthgPort;        
}

The EdgeServerConn.ned

    package org.car2x.veins.modules.EdgeComputing;

import org.car2x.veins.base.modules.*;
import org.car2x.veins.modules.nic.Nic80211p;
import org.car2x.veins.modules.EdgeComputing.*;
import org.car2x.veins.modules.EdgeComputing.connectedApplications.*;

module EdgeServerConn
{
    parameters:
    //    string applType= default("EdgeApp"); //type of the application layer
        string nicType = default("Nic80211p"); // type of network interface card
        @display("i=device/accesspoint");
    gates:
        input veinsradioIn; // gate for sendDirect
        inout ethg[2] @labels(EtherFrame-conn);
    submodules:
        appl: EdgeApplConn{
            parameters:
                @display("p=60,50");
        }

        nic: <nicType> like org.car2x.veins.modules.nic.INic80211p {
            parameters:
                @display("p=60,166");
        }

        mobility: BaseMobility {
            parameters:
                @display("p=130,172;i=block/cogwheel");
        }
        
    connections:
        nic.upperLayerOut --> appl.lowerLayerIn;
        nic.upperLayerIn <-- appl.lowerLayerOut;
        nic.upperControlOut --> appl.lowerControlIn;
        nic.upperControlIn <-- appl.lowerControlOut;

        veinsradioIn --> nic.radioIn;
        ethg[0] <--> appl.ControlEthgPort;
        ethg[1] <--> appl.DataEthgPort;
}