When working with IoT, typical phisical possible issue is conenctivity from device/gateway to the cloud. In a case of IotHub there are several components, which establich different kind of connections to IotHub.
Following commang validates connectivity to IotHub via 5671. Note that protocol used for connectivity can be changed.
docker exec -it edgeHub nc -vz daenet-iothub.azure-devices.net 5671
Source: https://github.com/Azure/iotedge/blob/master/doc/networking.md#upstream-protocol