diff --git a/config/initializers/doorkeeper_openid_connect.rb b/config/initializers/doorkeeper_openid_connect.rb
index bf1839682..86e5a3ca5 100644
--- a/config/initializers/doorkeeper_openid_connect.rb
+++ b/config/initializers/doorkeeper_openid_connect.rb
@@ -48,7 +48,7 @@
     user_id = user['id']
     user_email = User.find(resource_owner.id).email
 
-    return { id: user_id, email: user_email }
+    { id: user_id, email: user_email }.to_json
 
     # or if you need pairwise subject identifier, implement like below:
     # Digest::SHA256.hexdigest("#{resource_owner.id}#{URI.parse(application.redirect_uri).host}#{'your_secret_salt'}")