Grandstream HT813 gateway configuration on compact mitel 5000

[Jackson]

Hello everyone, there you go, I recently acquired a HT813 gateway from Grandstream.
I aim to use this gateway to connect my fixed line from Orange to my Mitel system.
Problem I tried to do the configurations but it doesn’t work, and I can’t find what it might be... If someone knows how I have to do the configurations on the HT813 gateway and also on the compact Mitel 5000, I am in charge!

Thank you.

[Jackson]

I'm sharing my current setup with you. If anyone can tell me what's going on, that would be great!
Honestly, I don't understand anything, but it might be the Mitel routing that's not working.
Except I have no idea what configurations are needed to make it work.
My setup is as an image in the PDF attached to this post