diff --git a/app/src/main/java/eu/faircode/email/FragmentIdentity.java b/app/src/main/java/eu/faircode/email/FragmentIdentity.java
index 0e06c79bc4..871f0df7a7 100644
--- a/app/src/main/java/eu/faircode/email/FragmentIdentity.java
+++ b/app/src/main/java/eu/faircode/email/FragmentIdentity.java
@@ -604,12 +604,13 @@ public class FragmentIdentity extends FragmentBase {
                         else
                             props.put("mail.smtps.localhost", host);
                     } else {
-                        String haddr = (ip instanceof Inet6Address ? "IPv6:" : "") + ip.getHostAddress();
+                        InetAddress localhost = InetAddress.getLocalHost();
+                        String haddr = "[" + (localhost instanceof Inet6Address ? "IPv6:" : "") + localhost.getHostAddress() + "]";
                         Log.i("Check local address=" + haddr);
                         if (starttls)
-                            props.put("mail.smtp.localaddress", haddr);
+                            props.put("mail.smtp.localhost", haddr);
                         else
-                            props.put("mail.smtps.localaddress", haddr);
+                            props.put("mail.smtps.localhost", haddr);
                     }
 
                     // Create session
diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index 5606a8c8af..35c0464adf 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -1920,12 +1920,13 @@ public class ServiceSynchronize extends LifecycleService {
             else
                 props.put("mail.smtps.localhost", ident.host);
         } else {
-            String haddr = (ip instanceof Inet6Address ? "IPv6:" : "") + ip.getHostAddress();
+            InetAddress localhost = InetAddress.getLocalHost();
+            String haddr = "[" + (localhost instanceof Inet6Address ? "IPv6:" : "") + localhost.getHostAddress() + "]";
             EntityLog.log(ServiceSynchronize.this, "Send local address=" + haddr);
             if (ident.starttls)
-                props.put("mail.smtp.localaddress", haddr);
+                props.put("mail.smtp.localhost", haddr);
             else
-                props.put("mail.smtps.localaddress", haddr);
+                props.put("mail.smtps.localhost", haddr);
         }
 
         // Create session