[Alertmanager] WebsiteNotHealthy https://webapp1.internal.softwareheritage.org/graphql/

Since 14h51 there is an alert:
Alert WARNING firing - admin/cluster-admin-rke2 - WebsiteNotHealthy - The production website https://webapp1.internal.softwareheritage.org/graphql/ is not healthy since more than 5m..

Here is the prometheus query that trigger this alert: query