diff --git a/lib/private/AppFramework/Http/Request.php b/lib/private/AppFramework/Http/Request.php
index f7d45630a81f2..c3e85379cc47d 100644
--- a/lib/private/AppFramework/Http/Request.php
+++ b/lib/private/AppFramework/Http/Request.php
@@ -676,7 +676,7 @@ public function getServerProtocol(): string {
 	 * @return string HTTP protocol. HTTP/2, HTTP/1.1 or HTTP/1.0.
 	 */
 	public function getHttpProtocol(): string {
-		$claimedProtocol = $this->server['SERVER_PROTOCOL'];
+		$claimedProtocol = $this->server['SERVER_PROTOCOL'] ?? '';
 
 		if (\is_string($claimedProtocol)) {
 			$claimedProtocol = strtoupper($claimedProtocol);