Hi @Brice187 did you fix it already?
We got also a different path and for us it is working. So if you go to kube-dev.iznet/alertmanager it is redirecting to kube-dev.iznet/alertmanager/graph?
What is the site showing mentioned in the error → https://kube-dev.iznet/alertmanager/api/v1/rules
Kind regards
Mathias