Ok,
little update, I’ve contacted the supplier and they gave me a new PSU, it dind’t work then after some talking with the support I got a new tube and now everything works.
I first replaced the PSU tried firing, nothing, then I replaced also the tube, tried firing it again and it worked seems to me like the tube was the faulty component.
Also bought some high voltage connectors so the replacement was pretty much straight forward.
So, here’s a big thank you for all of you for your help.