diff --git a/inc/admin/namespace.php b/inc/admin/namespace.php
index 1b8dadd..32fd366 100644
--- a/inc/admin/namespace.php
+++ b/inc/admin/namespace.php
@@ -55,7 +55,7 @@ function update_catalog() {
 		delete_blog_option( $blog_id, \Aldine\Admin\BLOG_OPTION );
 		update_site_meta( $blog_id, BookDataCollector::IN_CATALOG, 0 );
 		// Exclude book when network option book directory non-catalog exclude is enabled
-		$option = get_site_option( pressbooks_sharingandprivacy_options, [], true );
+		$option = get_site_option( 'pressbooks_sharingandprivacy_options', [], true );
 		if (
 			isset( $option[ SharingAndPrivacyOptions::NETWORK_DIRECTORY_EXCLUDED ] ) &&
 			( (bool) $option[ SharingAndPrivacyOptions::NETWORK_DIRECTORY_EXCLUDED ] === true )