diff --git a/app/models/transaction/slack.rb b/app/models/transaction/slack.rb
index ae5ec7a95..300ba2d2d 100644
--- a/app/models/transaction/slack.rb
+++ b/app/models/transaction/slack.rb
@@ -181,7 +181,7 @@ class Transaction::Slack
         result = notifier.ping result[:subject],
                                attachments: [attachment]
       end
-      if !result.success?
+      if !result.empty? && !result[0].success?
         if sent_value
           Cache.delete(cache_key)
         end