diff --git a/lib/private/Collaboration/Collaborators/MailPlugin.php b/lib/private/Collaboration/Collaborators/MailPlugin.php
index aa317ec17204f..27999bf933fc0 100644
--- a/lib/private/Collaboration/Collaborators/MailPlugin.php
+++ b/lib/private/Collaboration/Collaborators/MailPlugin.php
@@ -186,7 +186,7 @@ public function search($search, $limit, $offset, ISearchResult $searchResult) {
 							return false;
 						}
 
-						if ($this->shareeEnumeration) {
+						if ($this->shareeEnumeration && isset($contact['CLOUD'])) {
 							try {
 								$cloud = $this->cloudIdManager->resolveCloudId($contact['CLOUD'][0]);
 							} catch (\InvalidArgumentException $e) {