When my hair fellout earlier this year, I had it cut short. When it grew in heaalthy, I colored it?

... with L'Oreal Light Ash Blonde.
Nothing changed. I'm still white.
Since then I've done three test strands with mediun golden brown, the brown with the ash, and the ash alone, all with 20% H2O2. Again I'm 100% white. What could be the reason?

Thanx,
A Former Hairdresser