This incident has been resolved.

We are seeing signs of Availability Zone connectivity improving and are continuing to monitor.

The Google Cloud status page has been updated to report further information, follow this link for details https://status.cloud.google.com/incidents/Xs2XTHzAVC9YnafnPyzj

Since 0600 UTC we have observed cluster node connectivity issues isolated to a single availability zone, GCP europe-west2-b. Atlas clusters are distributed across multiple AZs and 3-node clusters can continue to serve reads and writes from nodes in the other 2 Availability Zones in this region. We are working with our partners to resolve the cause of the issue and restore service to the affected nodes.