diff --git a/apps/provisioning_api/lib/Controller/GroupsController.php b/apps/provisioning_api/lib/Controller/GroupsController.php
index e7e2a666b7bb4..46de5395a6560 100644
--- a/apps/provisioning_api/lib/Controller/GroupsController.php
+++ b/apps/provisioning_api/lib/Controller/GroupsController.php
@@ -271,6 +271,9 @@ public function updateGroup(string $groupId, string $key, string $value): DataRe
 
 		if ($key === 'displayname') {
 			$group = $this->groupManager->get($groupId);
+			if ($group === null) {
+				throw new OCSException('Group does not exist', OCSController::RESPOND_NOT_FOUND);
+			}
 			if ($group->setDisplayName($value)) {
 				return new DataResponse();
 			}