diff --git a/app/controllers/api/account.php b/app/controllers/api/account.php
index cd997d3be..abe642b51 100644
--- a/app/controllers/api/account.php
+++ b/app/controllers/api/account.php
@@ -1714,6 +1714,11 @@ App::patch('/v1/account/sessions/:sessionId')
                 $appSecret = $project->getAttribute('providers', [])[$provider.'Secret'] ?? '{}';
 
                 $className = 'Appwrite\\Auth\\OAuth2\\'.\ucfirst($provider);
+             
+                if (!\class_exists($className)) {
+                    throw new Exception('Provider is not supported', 501);
+                }
+
                 $oauth2 = new $className($appId, $appSecret, '', [], []);
 
                 $oauth2->refreshTokens($refreshToken);
diff --git a/src/Appwrite/Auth/OAuth2.php b/src/Appwrite/Auth/OAuth2.php
index 9b4c3b938..4eafba761 100644
--- a/src/Appwrite/Auth/OAuth2.php
+++ b/src/Appwrite/Auth/OAuth2.php
@@ -124,7 +124,7 @@ abstract class OAuth2
     public function getAccessToken(string $code):string
     {
         $tokens = $this->getTokens($code);
-        return $tokens['access_token'];
+        return $tokens['access_token'] ?? '';
     }
 
     /**
@@ -135,7 +135,7 @@ abstract class OAuth2
     public function getRefreshToken(string $code):string
     {
         $tokens = $this->getTokens($code);
-        return $tokens['refresh_token'];
+        return $tokens['refresh_token'] ?? '';
     }
 
     /**
@@ -146,7 +146,7 @@ abstract class OAuth2
     public function getAccessTokenExpiry(string $code):string
     {
         $tokens = $this->getTokens($code);
-        return $tokens['expires_in'];
+        return $tokens['expires_in'] ?? '';
     }
 
     // The parseState function was designed specifically for Amazon OAuth2 Adapter to override.