Audi A3 1999 1.6 Immo Issue

Hi to all friends.
Hope you are doing well.

I have an Audi car:
Audi A3
Year 1998-1999
1.6 Benzine

The problem is that the guy has three keys. All of keys do not start engine.
I mean the engine starts but it goes off after 2 seconds with three keys.
I repeat with three keys.

The transponder is:
ID 48 CRYPTO LOCKED

Where might be the problem? Can it be that three keys are failed?
If I want to turn Immo OFF, what eeprom might be inside?

Thank you very very much.