diff --git a/app/src/main/java/eu/faircode/email/Core.java b/app/src/main/java/eu/faircode/email/Core.java
index 2942ba4c24..d9ff8a7055 100644
--- a/app/src/main/java/eu/faircode/email/Core.java
+++ b/app/src/main/java/eu/faircode/email/Core.java
@@ -2174,12 +2174,12 @@ class Core {
                     String r = ((InternetAddress) reply).getAddress();
                     int rat = (r == null ? -1 : r.indexOf('@'));
                     if (rat > 0) {
-                        String rdomain = r.substring(rat + 1);
+                        String rdomain = ConnectionHelper.getParentDomain(r.substring(rat + 1));
                         for (Address from : message.from) {
                             String f = ((InternetAddress) from).getAddress();
                             int fat = (f == null ? -1 : f.indexOf('@'));
                             if (fat > 0) {
-                                String fdomain = f.substring(fat + 1);
+                                String fdomain = ConnectionHelper.getParentDomain(f.substring(fat + 1));
                                 if (!rdomain.equalsIgnoreCase(fdomain)) {
                                     if (message.warning == null)
                                         message.warning = context.getString(R.string.title_reply_domain, fdomain, rdomain);