When you make the following configuration changes, the Update All option is the only option available and your site is unavailable while the update occurs:
If you change Identity Server configuration that is used for authentication (Access Gateways > Edit > Reverse Proxy/Authentication, then select a different value for the Identity Server Cluster option).
If you select a different reverse proxy to use for authentication (Access Gateways > Edit > Reverse Proxy/Authentication, then select a different value for the Reverse Proxy option).
If you modify the protocol or port of the authenticating reverse proxy (Access Gateways > Edit > Reverse Proxy/Authentication > [Name of Reverse Proxy], then change the SSL options or the port options).
If you modify the published DNS name of the authentication proxy service (Access Gateways > Edit > Reverse Proxy/Authentication > [Name of Reverse Proxy] > [Name of First Proxy Service], then modify the Published DNS Name option).