customer modified the password for user=root which has impact on http, https, telnet, ssh (CLI) access but still the device discovery tool, using Advanced device discovery protocol (ADDP) requires the old password.
The password for user = root, which you modify via the web page, does not impact the access via the ADDP protocol. Via the ADDP protocol as used by the Digi Device Discovery Tool, a different user with name=addp is used.
E.g. to change the password for ADDP access via CLI, use the command:
see the Command Reference:
This holds for devices with unique passwords running the NDS plug and play firmware, e.g. like the Connect ME -S or Connect ME 9210 -S.