diff --git a/roles/opendkim/files/opendkim.conf b/roles/opendkim/files/opendkim.conf
index 03353770c0..c50d1d1692 100644
--- a/roles/opendkim/files/opendkim.conf
+++ b/roles/opendkim/files/opendkim.conf
@@ -131,3 +131,7 @@ OversignHeaders	From
 ##  caching service. Useful if the nameserver being used by the filter is
 ##  not local.
 # QueryCache	yes
+#
+# We need to increase the default header size because notifs adds a X-fedmsg header for
+# each message in a digest.
+MaximumHeaders 262144