diff --git a/interface/web/mail/lib/lang/de_mail_alias.lng b/interface/web/mail/lib/lang/de_mail_alias.lng
index acb0366264ee0f8dfc15245391f90426287d3d08..519044656678f2aa2be186ddd31a4f2e94986eda 100644
--- a/interface/web/mail/lib/lang/de_mail_alias.lng
+++ b/interface/web/mail/lib/lang/de_mail_alias.lng
@@ -7,6 +7,7 @@ $wb['email_error_unique'] = 'Doppelte E-Mail-Adresse.';
 $wb['no_domain_perm'] = 'Sie haben keine Berechtigung für diese Domain.';
 $wb['destination_error_isemail'] = 'Zieladresse ist ungültig.';
 $wb['limit_mailalias_txt'] = 'Die maximale Anzahl an E-Mail-Aliassen für ihr Konto wurde erreicht.';
-$wb['duplicate_mailbox_txt'] = 'Es existiert bereits eine Mailbox mit dieser E-Mail-Adresse';
+$wb['duplicate_mailbox_txt'] = 'Es existiert bereits eine Mailbox mit dieser E-Mail-Adresse.';
 $wb['domain_txt'] = 'Domain';
+$wb["duplicate_email_alias_txt"] = 'Dieser E-Mail-Alias existiert bereits.';
 ?>
diff --git a/interface/web/mail/lib/lang/en_mail_alias.lng b/interface/web/mail/lib/lang/en_mail_alias.lng
index f1c715a05d8c8694484621930fcea3fd1ad428df..02f753c492949b2f94da900d1540d315d89edcbb 100644
--- a/interface/web/mail/lib/lang/en_mail_alias.lng
+++ b/interface/web/mail/lib/lang/en_mail_alias.lng
@@ -7,6 +7,7 @@ $wb["email_error_unique"] = 'Duplicate Emailaddress.';
 $wb["no_domain_perm"] = "You have no permission for this domain.";
 $wb["destination_error_isemail"] = 'Destination Emailaddress is invalid.';
 $wb["limit_mailalias_txt"] = 'The max. number of email aliases for your account is reached.';
-$wb["duplicate_mailbox_txt"] = 'There is already a mailbox with this email address';
+$wb["duplicate_mailbox_txt"] = 'There is already a mailbox with this email address.';
 $wb['domain_txt'] = 'Domain';
+$wb["duplicate_email_alias_txt"] = 'This email alias does already exist.';
 ?>
diff --git a/interface/web/mail/mail_alias_edit.php b/interface/web/mail/mail_alias_edit.php
index b7140b03d890af62e2d1537b24519760fb8b76c2..ebc3a876256686e6de73a2679a38fb46eaa1445b 100644
--- a/interface/web/mail/mail_alias_edit.php
+++ b/interface/web/mail/mail_alias_edit.php
@@ -126,6 +126,15 @@ class page_action extends tform_actions {
 		if($tmp['number'] > 0) $app->tform->errorMessage .= $app->tform->lng("duplicate_mailbox_txt")."<br>";
 		unset($tmp);
 		
+		//* Check if email alias exists
+		if($this->id > 0) {
+			$tmp = $app->db->queryOneRecord("SELECT count(forwarding_id) as number FROM mail_forwarding WHERE source = '".$app->db->quote($this->dataRecord["source"])."' AND destination = '".$app->db->quote($this->dataRecord["destination"])."' AND forwarding_id != ".$this->id);
+		} else {
+			$tmp = $app->db->queryOneRecord("SELECT count(forwarding_id) as number FROM mail_forwarding WHERE source = '".$app->db->quote($this->dataRecord["source"])."' AND destination = '".$app->db->quote($this->dataRecord["destination"])."'");
+		}
+		if($tmp['number'] > 0) $app->tform->errorMessage .= $app->tform->lng("duplicate_email_alias_txt")."<br>";
+		unset($tmp);
+		
 		parent::onSubmit();
 	}
 	
diff --git a/interface/web/sites/lib/lang/de_web_domain.lng b/interface/web/sites/lib/lang/de_web_domain.lng
index 2cfebf21659fa69c797a5606b7975376149babee..a2b31c7a4ba507f8bf5f5cc3e2adaab588ab3496 100644
--- a/interface/web/sites/lib/lang/de_web_domain.lng
+++ b/interface/web/sites/lib/lang/de_web_domain.lng
@@ -89,4 +89,6 @@ $wb['pm_max_children_error_regex'] = 'PHP-FPM pm.max_children mu&szlig; eine pos
 $wb['pm_start_servers_error_regex'] = 'PHP-FPM pm.start_servers mu&szlig; eine positive ganze Zahl sein.';
 $wb['pm_min_spare_servers_error_regex'] = 'PHP-FPM pm.min_spare_servers mu&szlig; eine positive ganze Zahl sein.';
 $wb['pm_max_spare_servers_error_regex'] = 'PHP-FPM pm.max_spare_servers mu&szlig; eine positive ganze Zahl sein.';
+$wb["hd_quota_error_regex"] = 'Harddisk Quota ist ungültig.';
+$wb["traffic_quota_error_regex"] = 'Traffic Quota ist ungültig.';
 ?>
diff --git a/interface/web/sites/lib/lang/en_web_domain.lng b/interface/web/sites/lib/lang/en_web_domain.lng
index b7fcc679f97dcef618129badd74a6bb7c87cab3a..3556cd30d32f76653118f158a1a0ffda77d094e8 100644
--- a/interface/web/sites/lib/lang/en_web_domain.lng
+++ b/interface/web/sites/lib/lang/en_web_domain.lng
@@ -89,4 +89,6 @@ $wb["pm_max_children_error_regex"] = 'PHP-FPM pm.max_children must be a positive
 $wb["pm_start_servers_error_regex"] = 'PHP-FPM pm.start_servers must be a positive integer value.';
 $wb["pm_min_spare_servers_error_regex"] = 'PHP-FPM pm.min_spare_servers must be a positive integer value.';
 $wb["pm_max_spare_servers_error_regex"] = 'PHP-FPM pm.max_spare_servers must be a positive integer value.';
+$wb["hd_quota_error_regex"] = 'Harddisk quota is invalid.';
+$wb["traffic_quota_error_regex"] = 'Traffic quota is invalid.';
 ?>
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