diff --git a/app/controllers/ontologies_controller.rb b/app/controllers/ontologies_controller.rb
index f47a16500..660f9fcde 100644
--- a/app/controllers/ontologies_controller.rb
+++ b/app/controllers/ontologies_controller.rb
@@ -588,6 +588,7 @@ def search_first_instance_id
 
   def keep_only_root_categories(categories)
     categories.select do |category|
+      next unless category.id
       category.id.start_with?(rest_url) || category.parentCategory.blank?
     end
   end
diff --git a/app/helpers/federation_helper.rb b/app/helpers/federation_helper.rb
index f0b2fc409..18cdb48fd 100644
--- a/app/helpers/federation_helper.rb
+++ b/app/helpers/federation_helper.rb
@@ -163,7 +163,7 @@ def canonical_ontology(ontologies)
   end
 
   def federation_portal_status(portal_name: nil)
-    Rails.cache.fetch("federation_portal_up_#{portal_name}", expires_in: 2.hours) do
+    Rails.cache.fetch("federation_portal_up_#{portal_name}", expires_in: 10.minutes) do
       portal_api = federated_portals&.dig(portal_name,:api)
       return false unless portal_api
       portal_up = false