diff --git a/src/kmkernel.cpp b/src/kmkernel.cpp
index 105063313..aafb9ee5d 100644
--- a/src/kmkernel.cpp
+++ b/src/kmkernel.cpp
@@ -750,7 +750,9 @@ void KMKernel::setAccountStatus(bool goOnline)
         const auto col = CommonKernel->collectionFromId(CommonKernel->outboxCollectionFolder().id());
         const qint64 nbMsgOutboxCollection = col.statistics().count();
         if (nbMsgOutboxCollection > 0) {
-            kmkernel->msgSender()->sendQueued();
+            if (!kmkernel->msgSender()->sendQueued()) {
+                KMessageBox::error(KMKernel::self()->mainWin(), i18n("Impossible to send email"), i18n("Send Email"));
+            }
         }
     }
 }
diff --git a/src/kmmainwidget.cpp b/src/kmmainwidget.cpp
index b47aec409..3dc186bdf 100644
--- a/src/kmmainwidget.cpp
+++ b/src/kmmainwidget.cpp
@@ -2330,7 +2330,9 @@ void KMMainWidget::slotUpdateOnlineStatus(KMailSettings::EnumNetworkState::type)
 void KMMainWidget::slotSendQueued()
 {
     if (kmkernel->msgSender()) {
-        kmkernel->msgSender()->sendQueued();
+        if (!kmkernel->msgSender()->sendQueued()) {
+            KMessageBox::error(this, i18n("Impossible to send email"), i18n("Send Email"));
+        }
     }
 }
 
@@ -2339,7 +2341,9 @@ void KMMainWidget::slotSendQueuedVia(MailTransport::Transport *transport)
 {
     if (transport) {
         if (kmkernel->msgSender()) {
-            kmkernel->msgSender()->sendQueued(transport->id());
+            if (!kmkernel->msgSender()->sendQueued(transport->id())) {
+                KMessageBox::error(this, i18n("Impossible to send email"), i18n("Send Email"));
+            }
         }
     }
 }