diff --git a/admin_domains.php b/admin_domains.php
index 4931a0fa..ce915bb4 100644
--- a/admin_domains.php
+++ b/admin_domains.php
@@ -700,6 +700,11 @@ if ($page == 'domains'
 					$issubof = '0';
 				}
 
+				if ($aliasdomain != 0 && $letsencrypt != 0)
+				{
+					standard_error('letsencryptdoesnotworkwithaliasdomains');
+				}
+
 				if ($domain == '') {
 					standard_error(array('stringisempty', 'mydomain'));
 				}
@@ -1497,6 +1502,11 @@ if ($page == 'domains'
 					$issubof = '0';
 				}
 
+				if ($aliasdomain != 0 && $letsencrypt != 0)
+				{
+					standard_error('letsencryptdoesnotworkwithaliasdomains');
+				}
+
 				if ($serveraliasoption != '1' && $serveraliasoption != '2') {
 					$serveraliasoption = '0';
 				}
diff --git a/customer_domains.php b/customer_domains.php
index 22ca19b6..c73bcd21 100644
--- a/customer_domains.php
+++ b/customer_domains.php
@@ -342,6 +342,11 @@ if ($page == 'overview') {
 					}
 				}
 
+				if ($aliasdomain != 0 && $letsencrypt != 0)
+				{
+					standard_error('letsencryptdoesnotworkwithaliasdomains');
+				}
+
 				// Temporarily deactivate ssl_redirect until Let's Encrypt certificate was generated
 				if ($ssl_redirect > 0 && $letsencrypt == 1) {
 					$ssl_redirect = 2;
@@ -605,6 +610,11 @@ if ($page == 'overview') {
 					$letsencrypt = '0';
 				}
 
+				if ($aliasdomain != 0 && $letsencrypt != 0)
+				{
+					standard_error('letsencryptdoesnotworkwithaliasdomains');
+				}
+
 				// Temporarily deactivate ssl_redirect until Let's Encrypt certificate was generated
 				if ($ssl_redirect > 0 && $letsencrypt == 1 && $result['letsencrypt'] != $letsencrypt) {
 					$ssl_redirect = 2;
diff --git a/lng/english.lng.php b/lng/english.lng.php
index 39e4f2d8..914dacfd 100644
--- a/lng/english.lng.php
+++ b/lng/english.lng.php
@@ -1934,6 +1934,7 @@ $lng['customer']['letsencrypt']['title'] = 'Use Let\'s Encrypt';
 $lng['customer']['letsencrypt']['description'] = 'Get a free certificate from <a href="https://letsencrypt.org">Let\'s Encrypt</a>. The certificate will be created and renewed automatically.<br><string class="red">ATTENTION:"</strong>This feature is still in beta.';
 $lng['error']['sslredirectonlypossiblewithsslipport'] = 'Using Let\'s Encrypt is only possible when the domain has at least one ssl-enabled IP/port combination assigned.';
 $lng['error']['nowildcardwithletsencrypt'] = 'Let\'s Encrypt cannot (yet) handle wildcard-domains. Please set the ServerAlias to WWW or disable it completely';
+$lng['error']['letsencryptdoesnotworkwithaliasdomains'] = "Usage of Let's Encrypt is not possible for aliasdomains at the moment. Please disable Let's Encrypt or AliasDomain";
 $lng['panel']['letsencrypt'] = 'Using Let\'s encrypt';
 $lng['crondesc']['cron_letsencrypt'] = 'updating Let\'s Encrypt certificates';
 $lng['serversettings']['letsencryptca']['title'] = "Let's Encrypt environment";
diff --git a/lng/german.lng.php b/lng/german.lng.php
index c460eafb..0193d637 100644
--- a/lng/german.lng.php
+++ b/lng/german.lng.php
@@ -1589,6 +1589,7 @@ $lng['customer']['letsencrypt']['title'] = 'Benutze Let\'s Encrypt';
 $lng['customer']['letsencrypt']['description'] = 'Holt ein kostenloses Zertifikat von <a href="https://letsencrypt.org">Let\'s Encrypt</a>. Das Zertifikat wird automatisch erstellt und verlängert.<br><string class="red">ACHTUNG:</strong>Dieses Feature befindet sich noch im Test.';
 $lng['error']['sslredirectonlypossiblewithsslipport'] = 'Die Nutzung von Let\'s Encrypt ist nur möglich, wenn die Domain mindestens eine IP/Port - Kombination mit aktiviertem SSL zugewiesen hat.';
 $lng['error']['nowildcardwithletsencrypt'] = 'Let\'s Encrypt kann (noch) nicht mit Wildcard-Domains umgehen. Bitte den ServerAlias auf WWW setzen oder deaktivieren';
+$lng['error']['letsencryptdoesnotworkwithaliasdomains'] = "Die Nutzung von Let's Encrypt ist mit AliasDomains derzeit nivcht möglich. Bitte Let's Encrypt oder AliasDomain deaktivieren";
 $lng['panel']['letsencrypt'] = 'Benutzt Let\'s encrypt';
 $lng['crondesc']['cron_letsencrypt'] = 'aktualisiert Let\'s Encrypt Zertifikate';
 $lng['serversettings']['letsencryptca']['title'] = "Let's Encrypt Umgebung";