Type: This is a 'Warning' message (Orange highlight).
Source: This originates from the Vector itself.
Symptoms: The device will most likely have additional more relevant errors present which will point to the actual issue. A device which is connected into Estate Manager, by definition, has already resolved the address to be able to do that. Therefore the device is probably suffering from other issues and is most likely disconnecting and reconnecting as it goes through a watchdog reset routine.
Cause: Something is preventing the DNS address resolution function from working correctly but as above, this is most likely an erroneous (red herring) message and there are other issues present on the device causing this error to be present as well.
Fix: To fix this issue, look for the other more relevant errors that are present and correct those.