diff --git a/mastus/mail.nix b/mastus/mail.nix
index 17518a4..055e003 100644
--- a/mastus/mail.nix
+++ b/mastus/mail.nix
@@ -43,6 +43,7 @@
       smtp_address_preference = ipv4
 
       message_size_limit = 81920000
+      mailbox_size_limit = 81920000
 
       # Do not send spam bounces
       # http://www.postfix.org/ADDRESS_VERIFICATION_README.html