Also update BYOIP page

Author: cicku

src/content/docs/byoip/troubleshooting.mdx

@@ -22,4 +22,9 @@ If you are experiencing packet loss as a result of an upstream ISP implementing
 
 ## Non-SNI support
 
+:::caution
+
 Currently, BYOIP cannot be used with [legacy custom certificates](/ssl/edge-certificates/custom-certificates/uploading/) to support <GlossaryTooltip term="Server Name Indication (SNI)" link="/ssl/reference/browser-compatibility/#non-sni-support">non-SNI</GlossaryTooltip> requests.
+:::
+
+An Address map can set the default SNI to enable non-SNI support, the default SNI can be any valid zone or subdomain owned by the account holding the BYOIP prefix. Refer to [Update Address Map API](/api/resources/addressing/subresources/address_maps/methods/edit/) for more information.