diff --git a/lib/pagelib.php b/lib/pagelib.php
index ec1b8d862fe8b..321bfc92bd7e3 100644
--- a/lib/pagelib.php
+++ b/lib/pagelib.php
@@ -1405,7 +1405,7 @@ public function set_title($title, bool $appendsitename = true) {
                 $sitenamedisplay = $CFG->sitenameintitle;
             }
             $site = get_site();
-            if (empty(trim($site->{$sitenamedisplay}))) {
+            if (empty(trim($site->{$sitenamedisplay} ?? ''))) {
                 // If for some reason the site name is not yet set, fall back to 'Moodle'.
                 $title .= self::TITLE_SEPARATOR . 'Moodle';
             } else {