Gateway Connection Issues impacting mailflow for Gsuite Customers

For impacted customers, we observed mail began to flow through their Tessian Gateway again sometime after 20:00 UTC.

On Proofpoint's end, Engineering investigated, but saw no changes and no errors in logging.

In fact, despite the mail logs saying the Tessian Gateway had refused the connection, we did not even see the attempts to connect reach our servers.

In parallel, we were tracking an open Google Workspace incident related to Gmail: https://www.google.com/appsstatus/dashboard/incidents/224ozRqzW4sFBDK8hLnT

Although the description and start time roughly lined up, there weren't enough details to say it was certainly the cause.

However, with the most recent update, we see that they've applied mitigation and have since seen recovery. Based off the update timestamp, this would have started sometime after 20:03 UTC. Since the timeline of the Google incident aligns with recovery we've seen on our end, it appears this Google Incident is the cause.

Proofpoint will continue to monitor, and look for additional information from Google to understand why this impacted the Tessian Gateway for Gsuite customers.

Customers can observe the backlog of emails processing through their gateway in their portal under Integrations > Email Deployments > Gateway > Alerting

Customers who disabled their routing rules, can consider re-enabling them as desired.

Over the last couple hours, we've seen an increase in reports from customers who use Gsuite as their email environment.

For impacted customers, the Proofpoint Inbound or Outbound gateway is rejecting connections from Gsuite, meaning mail may be delayed.
Engineering is actively engaged and investigating the cause.

In the meantime, we would encourage customers to disable routing to the Gateway in their Google Admin center to minimize impact. This can be done in the admin center by following these instructions:
Go to: G Suite → Gmail → Advanced Settings
In the Compliance section, disable the following rule(s):
- “Tessian Inbound” & “Tessian Outbound”

We will update once we have identified the cause, or additional viable workarounds.