Hi @Shadius
1. Hope your MX68 is Live on the Meraki Dashboard.
2. By default, MS120 will search for the internet on VLAN1.
If this a new setup. You may start with default configuration on MX68 and MS120. They should work seamlessly. Once the devices are live you may update the configuration as needed.
Else you may need to login to the switch Manually and configure the appropriate IP and VLAN settings from the Local Status page for the switch to reach the cloud.
Hope the following is your network connectivity.
Regards,
Ajit
AjitsNW@gmail.com
www.ajit.network