We can see that there is a server host

resources/pop3/pop3resource.cpp

@@ -459,7 +459,7 @@ void POP3Resource::loginJobResult(KJob *job)
         if (job->error() == KIO::ERR_CANNOT_LOGIN) {
             mAskAgain = true;
         }
-        cancelSync(i18n("Unable to login to the server %1.", mSettings.host())
+        cancelSync(i18n("Unable to login to the server \"%1\".", mSettings.host())
                    +QLatin1Char('\n') + job->errorString());
     } else {
         advanceState(List);