diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index 7d803c50a8..49c32da54f 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -1464,6 +1464,7 @@ public class ServiceSynchronize extends LifecycleService {
 
         // Create session
         Properties props = MessageHelper.getSessionProperties(ident.auth_type, ident.insecure);
+        props.put("mail.smtp.localhost", "localhost.localdomain.");
         final Session isession = Session.getInstance(props, null);
 
         // Create message