Your boiler is currently in a mandatory waiting period, meaning it is simply resting before it tries to restart itself.

waiting-time; 3 to 10 minutes

What causes this fault?

This fault occurs when the boiler tries to light the gas but cannot detect a steady flame to confirm it is safe to continue. The most common reasons are worn-out sensors that can no longer 'see' the flame, a faulty ignition spark, or an issue with the gas supply preventing the burner from firing up correctly.