Unable to add alert manager config

[babvin]

#cortextool alertmanager load cortexam.yaml --address=http://10.43.247.110:8080 --id=100

ERRO[0000] server returned HTTP status 400 Bad Request: error validating Alertmanager config: mkdir /tmp/validate-config-fake2832549557: read-only file system fields.msg="error validating Alertmanager config: mkdir /tmp/validate-config-fake2832549557: read-only file system" status="400 Bad Request"
cortextool: error: server returned HTTP status 400 Bad Request: error validating Alertmanager config: mkdir /tmp/validate-config-fake2832549557: read-only file system, try --help

level=warn ts=2023-06-15T15:13:25.386549127Z caller=api.go:138 component=MultiTenantAlertmanager org_id=fake msg="error validating Alertmanager config" err="mkdir /tmp/validate-config-fake2832549557: read-only file system"

I'm using Helm chart 2.1
❯ k describe deploy cortex-alertmanager -n cortex
Name: cortex-alertmanager
Namespace: cortex
CreationTimestamp: Thu, 15 Jun 2023 12:48:21 +0000
Labels: app.kubernetes.io/component=alertmanager
app.kubernetes.io/instance=cortex
app.kubernetes.io/managed-by=Helm
app.kubernetes.io/name=cortex
app.kubernetes.io/part-of=memberlist
app.kubernetes.io/version=v1.14.1
helm.sh/chart=cortex-2.1.0
Annotations: deployment.kubernetes.io/revision: 2
meta.helm.sh/release-name: cortex
meta.helm.sh/release-namespace: cortex