Your Carloop probably doesn't have the socketcan firmware running on it yet.
Here's how you can get the socketcan app flashed to your Carloop.
Open the Particle Web IDE to the socketcan app: https://build.particle.io/libs/carloop/1.1.0/tab/example/socketcan_serial.cpp
Click on the Use this example button.
At this point you can choose to flash over USB or through the cellular connection.
To flash through cellular, simply click the lightning bolt icon. It will warn you that it uses some of your monthly data allowance. That's fine to get started and if you don't flash too often.
If you want to save data you can flash through USB.
First download the firmware you'll be flashing by clicking the cloud download button from the Code button in the Web IDE.
Install the Particle command line interface. Here's the Windows installer link: https://binaries.particle.io/cli/installer/windows/ParticleCLISetup.exe
First put the Electron in device firmware update mode (DFU) by pressing MODE then tapping RESET, and holding MODE until it blinks yellow. Then flash the app you downloaded.
particle flash --usb C:\Users\myuser\Downloads\firmware.bin