Update index.mdx

Advanced cert only covers the zone and the respective subdomains related to the zone.

Author: omarshariff316

src/content/docs/ssl/edge-certificates/advanced-certificate-manager/index.mdx

@@ -50,6 +50,8 @@ Advanced certificates are not used with [Cloudflare Pages](/pages/) nor [R2](/r2
 
 Advanced certificates are [Domain Validated (DV)](/ssl/concepts/#validation-level). If your organization needs Organization Validated (OV) or Extended Validation (EV) certificates, refer to [Custom certificates](/ssl/edge-certificates/custom-certificates/). <br/>
 
+Advanced Certificates do not cover multiple different domains. For MDC, check the Cloudflare for SaaS product.
+
 ## Related resources
 
 <DirectoryListing />