add project.nil? in

app/queries/blockchain/balance_query.rb

@@ -13,6 +13,9 @@ class Blockchain::BalanceQuery < ApplicationQuery
       result_list = []
       token_list.each do |t|
         project = Project.find_by(id: t['token_name'].to_i)
+        if project.nil?
+          next
+        end
         owner = User.find_by(id: project.user_id)
         if owner.nil? || project.nil?
         else