You have renewed your Citrix ssl certificate but find your external users are no longer able to access citrix.
You receive a page can not be displayed error.
You are also unable to start the Secure Gateway Service and receive the below error:

Certificate supplied is not valid for current date

The new certificate must be selected through the Citrix CSG configuration service wizard before the service will start

1) Access the CSG configuration service wizard through start>programs>citrix on the CSG server
2) Click next until you reach the certificates window
3) Select the new certificate from the list, click next, next and finish to start the Secure Gateway Service