diff --git a/app/services/group_message.rb b/app/services/group_message.rb
index 2980f8ff5..5fd8a9a2c 100644
--- a/app/services/group_message.rb
+++ b/app/services/group_message.rb
@@ -43,7 +43,7 @@ class GroupMessage
 
   def message_params
     @message_params ||= begin
-      h = @opts[:message_params]||{}
+      h = {base_url: Discourse.base_url}.merge(@opts[:message_params]||{})
       if @opts[:user]
         h.merge!({
           username: @opts[:user].username,
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index ff79017f8..ede9bab57 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -958,18 +958,18 @@ en:
     user_automatically_blocked:
       subject_template: "New user %{username} blocked via flags"
       text_body_template: |
-        This is an automated message to inform you that the new user [%{username}](%{user_url}) was automatically blocked because multiple users flagged %{username}'s post(s).
+        This is an automated message to inform you that the new user [%{username}](%{base_url}%{user_url}) was automatically blocked because multiple users flagged %{username}'s post(s).
 
-        Please [review the flags](/admin/flags). If %{username} was incorrectly blocked from posting, click the unblock button on [the admin page for this user](%{user_url}).
+        Please [review the flags](%{base_url}/admin/flags). If %{username} was incorrectly blocked from posting, click the unblock button on [the admin page for this user](%{base_url}%{user_url}).
 
         This threshold can be changed via the `block_new_user` site settings.
 
     spam_post_blocked:
       subject_template: "New user %{username} blocked for repeated links"
       text_body_template: |
-        This is an automated message to inform you that the new user [%{username}](%{user_url}) tried to create multiple posts with links to %{domains}, but they were blocked from further posting to avoid spam.
+        This is an automated message to inform you that the new user [%{username}](%{base_url}%{user_url}) tried to create multiple posts with links to %{domains}, but they were blocked from further posting to avoid spam.
 
-        Please [review the user](%{user_url}).
+        Please [review the user](%{base_url}%{user_url}).
 
         This threshold can be changed via the `newuser_spam_host_threshold` site setting.