Agent cannot connect to gitlab KAS Server

How to Use GitLab Self-managed
1

Hi,
We have an error when trying to connect an agentk via internet to our on-premise gitlab.

gitlab.rb (redacted)

gitlab_kas['enable'] = true
gitlab_kas['gitlab_address'] = 'https://gitlab.mydomain.tld'
gitlab_kas['log_level'] = 'debug'
gitlab_rails['gitlab_kas_external_url'] = 'wss://gitlab.mydomain.tld/-/kubernetes-agent/'
gitlab_rails['gitlab_kas_internal_url'] = 'grpc://localhost:8153'
gitlab_rails['gitlab_kas_external_k8s_proxy_url'] = 'https://gitlab.mydomain.tld/-/kubernetes-agent/'
gitlab_kas['env'] = {
    "http_proxy" => "http://myinternalproxy",
    "https_proxy" => "http://myinternalproxy",
    "no_proxy" => "localhost,127.0.0.1,gitlab.mydomain.tld"
}

AgentK Helm command:

helm upgrade --install testk8sagent gitlab/gitlab-agent \
    --namespace gitlab-agent-testk8sagent \
    --create-namespace \
    --set image.tag=v15.8.0 \
    --set config.token=aTOKEN \
    --set config.kasAddress=wss://gitlab.mydomain.tld:443/-/kubernetes-agent/

Error:

{"level":"error","time":"2023-01-26T15:51:27.112Z","msg":"Error handling a connection","mod_name":"reverse_tunnel","error":"Connect(): rpc error: code = Unavailable desc = connection error: desc = \"transport: Error while dialing failed to WebSocket dial: failed to send handshake request: Get \\\"https://gitlab.mydomain.tld:443/-/kubernetes-agent/\\\": dial tcp 111:222:33:44:443: i/o timeout\""}```