diff --git a/app/services/polymorphic_object_finder.rb b/app/services/polymorphic_object_finder.rb
index 8ffd78734cb9e79c80776c89dfabe61af0540e85..51517d8d082518f79ed66cc7d7fcd8c58ce199c8 100644
--- a/app/services/polymorphic_object_finder.rb
+++ b/app/services/polymorphic_object_finder.rb
@@ -7,7 +7,7 @@ class PolymorphicObjectFinder
     key_type = "#{key}_type".to_sym
     model_name = only.any? ? only.detect { |item| item == params[key_type] } : params[key_type]
     return if model_name.nil?
-    model = model.constantize
+    model = model_name.constantize
     id = params[key_id]
     model.where(university: university).find(id)
   end