diff --git a/docs/configuration/storage.md b/docs/configuration/storage.md
index 539898e11..697c2c88b 100644
--- a/docs/configuration/storage.md
+++ b/docs/configuration/storage.md
@@ -1,5 +1,7 @@
 # Storage
 
+When configuring an object storage backend, the `storage-s3-endpoint` **must not** include the bucket name. That's what `s3-bucket-name` is for. Using subfolders in a bucket isn't currently supported.
+
 ## Settings
 
 ```yaml