[Rules] Update troubleshooting.mdx (#28769)

Link to custom rules

Author: luishcardoso

src/content/docs/rules/custom-errors/troubleshooting.mdx

@@ -8,7 +8,7 @@ sidebar:
 
 ## Cannot preview error page
 
-If Cloudflare cannot load your site or you have blocked the United States (US) via [IP Access rules](/waf/tools/ip-access-rules/) or WAF custom rules, publishing and previewing a custom error page might not work.
+If Cloudflare cannot load your site or you have blocked the United States (US) via [IP Access rules](/waf/tools/ip-access-rules/) or [WAF custom rules](/waf/custom-rules/), publishing and previewing a custom error page might not work.
 
 A common error might look like the following: `Error fetching page: Fetch failed, https://example.com/ipcountryblock.html returned 403 (Code: 1202)`.