Car Alarm System: AI & Immobilizer for Audi A6 4B

Hello,

My Audi A6 4B AYM starts briefly but then immediately shuts off.
When the ignition is turned on, only the warning lights illuminate on the instrument cluster.
not including lighting, mileage, clock, radio, etc.
No communication with the MSG (Modular Service Gateway) is possible via VAG-COM.
If I unplug the blue AI connector and plug it back in immediately,
My dashboard lights up, and the engine starts!

After that, it was possible to read the error memory, and there were 2 errors.
1. Immobilizer.
Bus communication to the AI has been interrupted.

Questions:
Which relay is responsible for powering the AI (Artificial Intelligence), MSG (Message Service), and WFS (Workflow System)?
or what could be the cause of the interruption?

Which component activates the cockpit functions (e.g., clock) when the door is opened?

Thank you for your help!