"Key Not Found" message on MFD

Hello All,

Admittedly it's for my VW Transporter 2014 but I do have VCDS...

Got a difficult one here, replaced the spare key battery (vehicle 10 years old - spare key never used), went out and unlocked the van, all ok - so locking is synced correctly. Key in ignition and then get the above error message, thought it weird as key is brand new.

The immobiliser chip is definitely in the key, have tried the resync methods detailed on line with door locking manually, button on the door, turning key and pressing lock or unlock etc. Nothing, then I tried the original key and it told me that was not recognised either - (brown trouser moment).

So plugged in VCDS, got the error messages relating to the immobiliser etc, but when ignotion was on also has flashing glow plug symbol.

Ran a scan and cleared all fault codes etc. Scanned again and cleared them, then original key worked. Left it a few hours and used original key - all worked ok.

Spare key still not playing ball, despite trying the same procedure mentioned above.

Any help or pointers greatly appreciated.