diff --git a/api/src/Accounts.php b/api/src/Accounts.php
index f7cc06c5ae..2ec473a64c 100644
--- a/api/src/Accounts.php
+++ b/api/src/Accounts.php
@@ -612,6 +612,20 @@ class Accounts
 			$account['account_firstname'] , $account['account_lastname'], $account_id);
 	}
 
+	/**
+	 * Return formatted username for Links, does NOT throw if $account_id is not int
+	 *
+	 * @param $account_id
+	 */
+	static function title($account_id)
+	{
+		if (empty($account_id) || !is_numeric($account_id) && !($id = self::getInstance()->name2id($account_id)))
+		{
+			return '#'.$account_id;
+		}
+		return self::username($id ?? $account_id);
+	}
+
 	/**
 	 * Format an email address according to the system standard
 	 *
diff --git a/api/src/Link.php b/api/src/Link.php
index 40a3bafeda..f86e96fd36 100644
--- a/api/src/Link.php
+++ b/api/src/Link.php
@@ -154,7 +154,7 @@ class Link extends Link\Storage
 			'name' => 'Accounts',
 			'icon' => 'addressbook/accounts',
 			'query' => 'EGroupware\\Api\\Accounts::link_query',
-			'title' => 'EGroupware\\Api\\Accounts::username',
+			'title' => 'EGroupware\\Api\\Accounts::title',
 			'view' => array('menuaction'=>'addressbook.addressbook_ui.view','ajax'=>'true'),
 			'view_id' => 'account_id'
 		),
@@ -914,7 +914,12 @@ class Link extends Link\Storage
 				}
 				else
 				{
-					$title = self::title($app,$id);	// no titles method --> fallback to query each link separate
+					try {
+						$title = self::title($app, $id);    // no titles method --> fallback to query each link separate
+					}
+					catch (\Throwable $e) {
+						$title = lang('Error').': '.$e->getMessage();
+					}
 				}
 			}
 			$titles[$id] = $title;