welcome to this moderated Azure community forum.
This is weird, normally, the connection strings (primary/secundary) are shown next to the two keys.
I just created this test device in the West Europe region (with autogenerated symmetric keys in the Azure portal):
How did you create this device? Using the Azure portal? Or using some script? If so, Can you share it?
A connection string is not that special:
HostName=[name of iot hub].azure-devices.net;DeviceId=[device name];SharedAccessKey=[one of the two keys]
But... it is strongly recommended to make use the Device Provisioning Service to control future IoT Hub selection/migration. This way, you do not need to access all your device to migrate to another IoT Hub.
Next to that, for Cloud to Device communication like a Direct Method call, you need to have the IoT Hub connectionstring!
See also this example in the documentation.
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