Fix typo: 'issues' to 'issued' in downstream device auth

Author: jlian

articles/iot-edge/how-to-authenticate-downstream-device.md

@@ -145,7 +145,7 @@ Next, [Retrieve and modify the connection string](#retrieve-and-modify-connectio
 
 ### X.509 CA-signed authentication
 
-For X.509 certificate authority (CA) signed authentication, you need a root CA certificate registered in IoT Hub that you use to sign certificates for your downstream device. Any device using a certificate that was issues by the root CA certificate or any of its intermediate certificates is permitted to authenticate.
+For X.509 certificate authority (CA) signed authentication, you need a root CA certificate registered in IoT Hub that you use to sign certificates for your downstream device. Any device using a certificate that was issued by the root CA certificate or any of its intermediate certificates is permitted to authenticate.
 
 For an introduction about using X.509 CA certificates to authenticate in IoT Hub, see the [benefits of X.509 CA certificate authentication](../iot-hub/authenticate-authorize-x509.md#benefits-of-x509-ca-certificate-authentication).