diff --git a/mod/ping.php b/mod/ping.php
index 1634ed725d..df6793f3c6 100644
--- a/mod/ping.php
+++ b/mod/ping.php
@@ -342,7 +342,7 @@ function ping_init(App $a)
 		array_walk($notifications, function (&$notification) {
 			if (empty($notification['photo'])) {
 				$contact = Contact::getByURL($notification['url'], false, ['micro', 'id', 'avatar']);
-				$notification['photo'] = Contact::getMicro($contact, $notif['photo']);
+				$notification['photo'] = Contact::getMicro($contact, $notification['photo']);
 			}
 
 			$notification['timestamp'] = DateTimeFormat::local($notification['date']);
diff --git a/src/Model/Profile.php b/src/Model/Profile.php
index b56df5bc5f..c5652c6f7a 100644
--- a/src/Model/Profile.php
+++ b/src/Model/Profile.php
@@ -166,7 +166,7 @@ class Profile
 			}
 		}
 
-		$profile = User::getOwnerDataById($user['uid'], false);
+		$profile = !empty($user['uid']) ? User::getOwnerDataById($user['uid'], false) : [];
 
 		if (empty($profile) && empty($profiledata)) {
 			Logger::log('profile error: ' . DI::args()->getQueryString(), Logger::DEBUG);
diff --git a/src/Model/User.php b/src/Model/User.php
index 2b70189505..76408df812 100644
--- a/src/Model/User.php
+++ b/src/Model/User.php
@@ -264,7 +264,7 @@ class User
 	 */
 	public static function getById($uid, array $fields = [])
 	{
-		return DBA::selectFirst('user', $fields, ['uid' => $uid]);
+		return !empty($uid) ? DBA::selectFirst('user', $fields, ['uid' => $uid]) : [];
 	}
 
 	/**
diff --git a/src/Security/FKOAuth1.php b/src/Security/FKOAuth1.php
index df6b38a171..d7549a1e7c 100644
--- a/src/Security/FKOAuth1.php
+++ b/src/Security/FKOAuth1.php
@@ -55,7 +55,7 @@ class FKOAuth1 extends OAuthServer
 		$a = DI::app();
 		$record = DBA::selectFirst('user', [], ['uid' => $uid, 'blocked' => 0, 'account_expired' => 0, 'account_removed' => 0, 'verified' => 1]);
 
-		if (!DBA::isResult($record)) {
+		if (!DBA::isResult($record) || empty($uid)) {
 			Logger::info('FKOAuth1::loginUser failure', ['server' => $_SERVER]);
 			header('HTTP/1.0 401 Unauthorized');
 			die('This api requires login');