diff -ruN a/conf/main.cf b/conf/main.cf
--- a/conf/main.cf	2019-06-16 02:33:53.000000000 +0200
+++ b/conf/main.cf	2020-11-09 18:22:06.436205639 +0100
@@ -401,6 +401,7 @@
 #alias_maps = hash:/etc/aliases
 #alias_maps = hash:/etc/aliases, nis:mail.aliases
 #alias_maps = netinfo:/aliases
+alias_maps = hash:/etc/postfix/aliases
 
 # The alias_database parameter specifies the alias database(s) that
 # are built with "newaliases" or "sendmail -bi".  This is a separate
@@ -411,6 +412,7 @@
 #alias_database = dbm:/etc/mail/aliases
 #alias_database = hash:/etc/aliases
 #alias_database = hash:/etc/aliases, hash:/opt/majordomo/aliases
+alias_database = $alias_maps
 
 # ADDRESS EXTENSIONS (e.g., user+foo)
 #