Immobilizer flashes fast

Hello, I have a Renault Twingo 1.2 16V Built 2001. My problem is that the immobiliser flashes quickly when I turn the key around, this is only the second key. I don’t know what the previous owners did either. The second key still had the original case, but this was broken so that I bought a new one. What could be the problem? Mfg Tanja