diff --git a/lib/User/Backend.php b/lib/User/Backend.php
index afd90e89..0b721859 100644
--- a/lib/User/Backend.php
+++ b/lib/User/Backend.php
@@ -235,7 +235,7 @@ public function getCurrentUserId(): string {
 
 		// get the bearer token from headers
 		$headerToken = $this->request->getHeader(Application::OIDC_API_REQ_HEADER);
-		if (!str_starts_with($headerToken, 'bearer ') && !str_starts_with($headerToken, 'Bearer ')) {
+		if (!str_starts_with(strtolower($headerToken), 'bearer ')) {
 			$this->logger->debug('No Bearer token');
 			return '';
 		}