# Supernode connection problem | Invalid timestamp **URL:** \ **Category:** Flower Help - Beginners\ **Created:** [May 27, 2025, 9:02am UTC](https://discuss.flower.ai/t/supernode-connection-problem-invalid-timestamp/977 "2025-05-27T09:02:57Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![stackpilot](https://avatars.discourse-cdn.com/v4/letter/s/f475e1/32.png) [@stackpilot](https://discuss.flower.ai/u/stackpilot)\ **Post date:** [May 27, 2025, 9:02am UTC](https://discuss.flower.ai/t/supernode-connection-problem-invalid-timestamp/977/1 "2025-05-27T09:02:57Z")
Hi all, I am trying to connect my supernodes to a superlink on a different machine in insecure mode. I got this exact setup running in the past (even yesterday), but all of a sudden these errors started coming up: ![image](https://europe1.discourse-cdn.com/flex013/uploads/flower/original/1X/b5ac2e3e5a3aa9ba04b65ea4f46f718ce80cded1.png) Yesterday, I was able to solve the issue by using the command `sudo systemctl enable systemd-timesyncd`. However, today I have the same issue again. What could be the reason for this? ---
**Author:** ![javier](https://dub1.discourse-cdn.com/flex013/user_avatar/discuss.flower.ai/javier/32/116_2.png) [@javier](https://discuss.flower.ai/u/javier)\ **Post date:** [May 27, 2025, 1:26pm UTC](https://discuss.flower.ai/t/supernode-connection-problem-invalid-timestamp/977/2 "2025-05-27T13:26:34Z")
Hello @stackpilot , the automatic node authentication feature relies on system clocks to be roughly in sync. There are a few seconds (5 seconds as of Flower 1.18.0) of grace in case there is some drift. Are both of your systems (where the `SuperLInk` and `SuperNode` run) are connected to the internet or alternative a server that provides a time synchronization via NTP ? Could you check if the times are in sync? e.g. by typing `date` on your terminal. Could you update your Flower installation in case you aren’t using the latest? ```shell pip install -U flwr ``` ---
**Author:** ![stackpilot](https://avatars.discourse-cdn.com/v4/letter/s/f475e1/32.png) [@stackpilot](https://discuss.flower.ai/u/stackpilot)\ **Post date:** [June 5, 2025, 9:37am UTC](https://discuss.flower.ai/t/supernode-connection-problem-invalid-timestamp/977/3 "2025-06-05T09:37:00Z")
Hello @javier , thank you for the quick reply. It looks like this solved the problem. So far, the “Invalid timestamp” error did not show up anymore. Thank you for the recommendation! Interestingly, `date` showed the same timestamps on both machines. Is the problem caused when there is even the slightest difference in the timestamps, maybe not even visible when using `date`? ---
**Author:** ![javier](https://dub1.discourse-cdn.com/flex013/user_avatar/discuss.flower.ai/javier/32/116_2.png) [@javier](https://discuss.flower.ai/u/javier)\ **Post date:** [June 5, 2025, 10:39am UTC](https://discuss.flower.ai/t/supernode-connection-problem-invalid-timestamp/977/4 "2025-06-05T10:39:03Z")
Hello @stackpilot, glad to hear that this error is not happening anymore. In the current version of Flower (1.18.0) a [5s drift it’s allowed](https://github.com/adap/flower/blob/7409111d83ff5d7a97acbfc84929ea76d9a8d086/framework/py/flwr/common/constant.py#L126) meaning that the times in different machines don’t have to exactly match. In a previous version of Flower this drift allowance didn’t exist which might explain errors if the system time is slightly off. By the way, how did you fixed it? did you updated your version of Flower? ---
**Author:** ![stackpilot](https://avatars.discourse-cdn.com/v4/letter/s/f475e1/32.png) [@stackpilot](https://discuss.flower.ai/u/stackpilot)\ **Post date:** [June 5, 2025, 11:35am UTC](https://discuss.flower.ai/t/supernode-connection-problem-invalid-timestamp/977/5 "2025-06-05T11:35:25Z")
I see, so Flower is not as strict with the timestamp anymore. Yes, I used `pip install -U flwr` as you suggested. Thank you again. ---
**Author:** ![system](https://europe1.discourse-cdn.com/flex013/uploads/flower/original/1X/bc7fe36843c391cbd0b4e8b6f48275961d356abc.png) [@system](https://discuss.flower.ai/u/system)\ **Post date:** [June 12, 2025, 11:35am UTC](https://discuss.flower.ai/t/supernode-connection-problem-invalid-timestamp/977/6 "2025-06-12T11:35:37Z")
Closed on June 12, 2025, 11:35am UTC This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.