diff --git a/doc/man/man5/slapo-pcache.5 b/doc/man/man5/slapo-pcache.5
index ca616721f0..daff804e55 100644
--- a/doc/man/man5/slapo-pcache.5
+++ b/doc/man/man5/slapo-pcache.5
@@ -49,7 +49,8 @@ with the
 .BR meta ,
 and
 .BR sql
-backends.
+backends. Please note that the underlying backend must have a configured
+.BR rootdn.
 .TP
 .B pcache <database> <max_entries> <numattrsets> <entry_limit> <cc_period> 
 The directive enables proxy caching in the current backend and sets general