Digi Discovery Tool "Error while saving the settings to the device. Authentication Failure (Code 1)"

While configuring network settings for a device, I’m getting “Error while saving the settings to the device. Authentication Failure (Code 1)”. I’ve confirmed the IP, subnet and gateway are correct for the vlan that my pc and terminal server are on, so I’m not sure where this one is coming from. Any help is appreciated.

Authentication Failure suggests that a password is set on the device. Were you prompted to input a password? If so, does that same password work if you (for example) try logging into the web interface of this device?