diff --git a/inc/metadata/namespace.php b/inc/metadata/namespace.php
index <HASH>..<HASH> 100644
--- a/inc/metadata/namespace.php
+++ b/inc/metadata/namespace.php
@@ -574,8 +574,8 @@ function section_information_to_schema( $section_information, $book_information 
 			];
 		}
 
-		if ( ! isset( $section_information['pb_section_license'] ) ) {
-			if ( isset( $book_information['pb_book_license'] ) ) {
+		if ( empty( $section_information['pb_section_license'] ) ) {
+			if ( ! empty( $book_information['pb_book_license'] ) ) {
 				$section_information['pb_section_license'] = $book_information['pb_book_license'];
 			} else {
 				$section_information['pb_section_license'] = 'all-rights-reserved';
@@ -583,6 +583,11 @@ function section_information_to_schema( $section_information, $book_information 
 		}
 
 		$licensing = new Licensing;
+
+		if ( ! $licensing->isSupportedType( $section_information['pb_section_license'] ) ) {
+			$section_information['pb_section_license'] = 'all-rights-reserved';
+		}
+
 		$section_schema['license'] = [
 			'@type' => 'CreativeWork',
 			'url' => $licensing->getUrlForLicense( $section_information['pb_section_license'] ),
Handle empty/garbage license values (#<I>)

* Handle situations where license has been set to empty string.



* Correct garbage license.