Key signal fault

Hi, the problem I have is I have lost my original key so I used my spare which I thought was adapted to the immobiliser system. On the dash display "Immobiliser Active" flashes and the vehicle wont start.

Using my VCDS there is a fault logged in the immobiliser "Key signal implausible" which wont clear, live data shows

1,Engine Start,permitted No

2,Engine (ECU),responds Yes

3,Key Status Yes

4,Number of,adapted Keys 1

The key signal is showing good number of keys adapted 1 which must be the old key.

The dealer near by has tryed re-adapting my spare key which apparently wont code?

Any ideas guys?