diff --git a/apps/dav/lib/CalDAV/Schedule/IMipService.php b/apps/dav/lib/CalDAV/Schedule/IMipService.php
index f7054eb2d34a4..54c0bc318494d 100644
--- a/apps/dav/lib/CalDAV/Schedule/IMipService.php
+++ b/apps/dav/lib/CalDAV/Schedule/IMipService.php
@@ -1110,7 +1110,7 @@ public function createInvitationToken(Message $iTipMessage, VEvent $vevent, int
 		$sequence = $iTipMessage->sequence;
 		$recurrenceId = isset($vevent->{'RECURRENCE-ID'})
 			? $vevent->{'RECURRENCE-ID'}->serialize() : null;
-		$uid = $vevent->{'UID'};
+		$uid = $vevent->{'UID'}?->getValue();
 
 		$query = $this->db->getQueryBuilder();
 		$query->insert('calendar_invitations')