How to troubleshoot an offline ACU?

Created by Hugo Fuhlendorff, Modified on Wed, 11 Jan 2023 at 09:05 AM by Hugo Fuhlendorff

The Hardware Dashboard in the Control Center indicates the online status of an ACU (Controller) in the Status column:


  • A green dot indicates the ACU is online and communicating normally
  • a yellow dot indicates the last message received from the ACU is more than 12 minutes old OR the VPN is down
  • A red dot indicates the ACU is offline: the last message received from the ACU is more than 60 minutes old OR more than 20 minutes old and the VPN is down




If your ACU is offline, try the following:

  1. Check that all network requirements are met: Network Requirements for Openpath

  2. Check that the Ethernet cable is securely connected to the ACU and to the switch, router, or modem

  3. Unplug the Ethernet cable from the ACU and plug it into a laptop to check if there is Internet service

  4. Check the status LED: What do the LEDs on ACUs/SDCs mean?

  5. Use the Remote Diagnostics tools in the Control Center: How do I troubleshoot ACUs and Smart Readers?

  6. Reboot the system by unplugging the ACU from power. Make sure to disconnect any backup battery first, and power it down for a MINIMUM of 30 seconds before powering it up.  Wait a few minutes before checking the Hardware Dashboard. You can attach the backup battery after it is up.

Note: You may need to refresh the page to see if the ACU changed from offline to online

If after trying all of the steps above and you cannot get the ACU back online we recommend reaching out to your installer to come out and check the hardware. If there have been network changes made we also recommend reaching out to your installer



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