Fixing typo

Fixing typo

Author: JackStromberg

articles/application-gateway/key-vault-certs.md

@@ -136,7 +136,7 @@ Add-AzApplicationGatewaySslCertificate -KeyVaultSecretId $secretId -ApplicationG
 Set-AzApplicationGateway -ApplicationGateway $appgw
 ```
 
-Once the commands have been executed, you can navigate to your Application Gateway in the Azure portal and select the Listeners tab.  Click Add Lister (or select an existing) and specify the Protocol to HTTPS.
+Once the commands have been executed, you can navigate to your Application Gateway in the Azure portal and select the Listeners tab.  Click Add Listener (or select an existing) and specify the Protocol to HTTPS.
 
 Under *Choose a certificate* select the certificate named in the previous steps.  Once selected, select  *Add* (if creating) or *Save* (if editing) to apply the referenced Key Vault certificate to the listener.