diff --git a/lib/fluent/plugin/out_forward.rb b/lib/fluent/plugin/out_forward.rb
index 712447b29f..b99cd5843b 100644
--- a/lib/fluent/plugin/out_forward.rb
+++ b/lib/fluent/plugin/out_forward.rb
@@ -402,8 +402,10 @@ def on_timer
           log.trace "sending heartbeat", host: n.host, port: n.port, heartbeat_type: @heartbeat_type
           n.usock = @usock if @usock
           n.send_heartbeat
-        rescue Errno::EAGAIN, Errno::EWOULDBLOCK, Errno::EINTR, Errno::ECONNREFUSED
-          log.debug "failed to send heartbeat packet", host: n.host, port: n.port, heartbeat_type: @heartbeat_type, error: $!
+        rescue Errno::EAGAIN, Errno::EWOULDBLOCK, Errno::EINTR, Errno::ECONNREFUSED, Errno::ETIMEDOUT => e
+          log.debug "failed to send heartbeat packet", host: n.host, port: n.port, heartbeat_type: @heartbeat_type, error: e
+        rescue => e
+          log.debug "unexpected error happen during heartbeat", host: n.host, port: n.port, heartbeat_type: @heartbeat_type, error: e
         end
       }
     end