diff --git a/interface/web/mail/lib/lang/de_mail_forward.lng b/interface/web/mail/lib/lang/de_mail_forward.lng
index a392ac4e33b18073de853b94f08b3f23510fc8a9..e0ef8c7d0c5667ca6d59aeb408d48d444c49882b 100644
--- a/interface/web/mail/lib/lang/de_mail_forward.lng
+++ b/interface/web/mail/lib/lang/de_mail_forward.lng
@@ -6,4 +6,5 @@ $wb['limit_mailforward_txt'] = 'Die maximale Anzahl an E-Mail Weiterleitungen f
 $wb['duplicate_mailbox_txt'] = 'Es existiert bereits ein E-Mail Konto mit dieser Adresse.';
 $wb['domain_txt'] = 'Domain';
 $wb['source_txt'] = 'Quell E-Mail Adresse';
+$wb['email_error_isemail'] = 'Bitte geben Sie eine gültige E-Mail Adresse an.';
 ?>
diff --git a/interface/web/mail/lib/lang/en_mail_forward.lng b/interface/web/mail/lib/lang/en_mail_forward.lng
index 4482593654011688141fa8015313989e199f8130..5d371eee7591c6e5037601e3ed620c429fdf9ea1 100644
--- a/interface/web/mail/lib/lang/en_mail_forward.lng
+++ b/interface/web/mail/lib/lang/en_mail_forward.lng
@@ -6,4 +6,5 @@ $wb["limit_mailforward_txt"] = 'The max. number of email forwarders for your acc
 $wb["duplicate_mailbox_txt"] = 'There is already a mailbox with this email address';
 $wb['domain_txt'] = 'Domain';
 $wb["source_txt"] = 'Source Email';
+$wb['email_error_isemail'] = 'Please enter a valid email address.';
 ?>