diff --git a/lib/bugsnag/session_tracker.rb b/lib/bugsnag/session_tracker.rb
index 074cd2edb..3caf8489b 100644
--- a/lib/bugsnag/session_tracker.rb
+++ b/lib/bugsnag/session_tracker.rb
@@ -69,7 +69,7 @@ def start_delivery_thread
             end
           end
         end
-        @delivery_thread = Concurrent::TimerTask.new(execution_interval: 30) do
+        @delivery_thread = Concurrent::TimerTask.execute(execution_interval: 30) do
           if @session_counts.size > 0
             send_sessions
           end