Sometimes there are issues connecting with the line using zencontrol commissioning tool, are there any requirements or restrictions?

There are some requirements that need to be met before the commission tool can connect to the controllers. 

1. The controllers must be registered to a site and the commission tool must be downloaded for the site the controllers are registered too.
   - If you can see a controller on the device scan, but cannot connect, try ensuring the devices are registered and then re-downloading the commission tool.
2. Some controllers may need a firmware update to support the current version of the commission tool.
   - Update the firmware on the devices by connecting them to the internet (use a temporary modem if internet is not yet connected to the site)
   - In the site settings, choose the firmware version (latest) and the time they should be updated in. To update immediately select a time window that includes the current time.
3. Some network settings may be blocking the access of the commission tool to the controllers. Follow the network set up instructions available on the zencontrol FAQ