Blank screen on logging in

i’m trying to build gitlab on Azure AKS behind a Web Application Firewall using the Helm charts. i get a log-in screen, but after logging in successfully i get a 404 error:

if i click “back”, i remain logged in, but with a blank screen:

this is my helm install command:
helm repo update
helm upgrade --install gitlab gitlab/gitlab
–timeout 600s
–set nginx-ingress.enabled=false
–set global.hosts.https=false
–set global.ingress.tls.enabled=false

i’m going to set up ssl on WAF.