Should allow non http referrers. Closes #2831

src/pages/api/send.ts

@@ -121,7 +121,7 @@ export default async (req: NextApiRequestCollect, res: NextApiResponse) => {
         urlPath = '/';
       }
 
-      if (referrerPath?.startsWith('http')) {
+      if (/^[\w-]+:\/\/\w+/.test(referrerPath)) {
         const refUrl = new URL(referrer);
         referrerPath = refUrl.pathname;
         referrerQuery = refUrl.search.substring(1);