Fixes #893 – Allow links to different subdomains on same domain as wiki

app/utils/isInternalUrl.js

@@ -4,11 +4,12 @@ import { parseDomain } from '../../shared/utils/domains';
 export default function isInternalUrl(href: string) {
   if (href[0] === '/') return true;
 
-  const outline = parseDomain(BASE_URL);
+  const outline = parseDomain(window.location.href);
   const parsed = parseDomain(href);
   if (
     parsed &&
     outline &&
+    parsed.subdomain === outline.subdomain &&
     parsed.domain === outline.domain &&
     parsed.tld === outline.tld
   ) {