Hi Sebastian
Thank you for the device serial number. This allows me to identify the firmware version the device shipped from the factory with.
The process & credentials to log in to the device depends on the firmware version running on the device.
mLinux firmware version 3.x and lower use (username) root (password) root.
mLinux firmware version 4.0.0 to 5.2 use (username) mtadm (password) root.
mLinux firmware version 5.2.1 or higher have no default username/password and you
would use a browser to browse to https://192.168.2.1 to commission the device
with a username and password.
SN#20695007 you provided shipped from MultiTech with mLinux version 5.1.8
If the device is still running firmware 5.1.8 then (username) mtadm (password) root.
If it is possible the mLinux firmware was updated then try accessing the device with web browser https://192.168.2.1 and see if the ‘commissioning’ page comes up.