diff --git a/data/conf/dovecot/dovecot.conf b/data/conf/dovecot/dovecot.conf
index 15be77fce..05d9264fa 100644
--- a/data/conf/dovecot/dovecot.conf
+++ b/data/conf/dovecot/dovecot.conf
@@ -53,7 +53,7 @@ mail_shared_explicit_inbox = yes
 mail_prefetch_count = 30
 passdb {
   driver = lua
-  args = file=/etc/dovecot/auth/passwd-verify.lua blocking=yes cache_key=%u:%w
+  args = file=/etc/dovecot/auth/passwd-verify.lua blocking=yes cache_key=%s:%u:%w
   result_success = return-ok
   result_failure = continue
   result_internalfail = continue