diff --git a/background.js b/background.js
index 673f9f4..2bf1d8b 100644
--- a/background.js
+++ b/background.js
@@ -249,7 +249,7 @@ function matchesSourceUrlFamily(source, candidateUrl, referenceUrl) {
     case 'qq-mail':
       return candidate.hostname === 'mail.qq.com' || candidate.hostname === 'wx.mail.qq.com';
     case 'mail-163':
-      return candidate.hostname === 'mail.163.com';
+      return candidate.hostname === 'mail.163.com' || candidate.hostname.endsWith('.mail.163.com');
     case 'inbucket-mail':
       return Boolean(reference)
         && candidate.origin === reference.origin
diff --git a/manifest.json b/manifest.json
index 7d486ff..355579a 100644
--- a/manifest.json
+++ b/manifest.json
@@ -42,7 +42,8 @@
     },
     {
       "matches": [
-        "https://mail.163.com/*"
+        "https://mail.163.com/*",
+        "https://*.mail.163.com/*"
       ],
       "js": ["content/utils.js", "content/mail-163.js"],
       "all_frames": true,