Proofpoint has confirmed the Emergency Allowlist has resolved the issue for impacted customers. We will continue to work with Google to understand what caused the false positive and prevent such issues in the future.

Please feel free to open a support case if you have any additional questions.

Google has applied an Emergency Allowlist for the EU portals, which should immediately stop "Dangerous site" warnings from appearing to users in Chrome and other browsers using Google Safe Browsing.
This action is a temporary fix while Google investigates the root cause of the false positive. Their product engineering team is working on a permanent resolution.
Testing from multiple stakeholders now shows that the error is gone in Chrome, Safari, and Firefox. Google has also confirmed that the EU portal  is no longer listed as dangerous on their Transparency Report.
We are checking with impacted customers to confirm the resolution from their side. Please report any continued issues so we can escalate with Google if needed.

We are aware of an issue affecting EU portal logins on Google Chrome. We are currently working with Google to have this reclassified as safe. At present, the issue appears limited to Google Safe Browsing, primarily impacting EU tenants. Other browsers, such as Safari and Firefox, are generally not affected, although some Safari users may see warnings depending on their security settings. Please note that the site itself is not compromised, and this warning is due to a misclassification.