How can I relight my Vokera Linea 7?

It is showing error code 01.


I have put it back to reset position and after 10 seconds put it back to the original position...this is not working. It says it is working for about 5 seconds and then the error code flashes up again.

Nothing has been touched on the boiler at ALL it just switched itself off. It is -3 degrees outside, and we are in dire need of the heat. Please help!