Cloudflare Access one-time PIN emails blocked by certain email security gateways, including Proofpoint

lowCloudflareAccessAug 31, 2026 20:16Duration: 1h 47m

authenticationconfigurationsecurity

Configuration ErrorSecurity IncidentAuthentication Issue

Summary

This incident has been resolved and the developer documentation has also been updated to reflect the same information: https://developers.cloudflare.com/cloudflare-one/integrations/identity-providers/one-time-pin/#allow-otp-emails-through-your-email-gateway

Impact

minor

Timeline

Aug 31, 2026 20:16

[investigating] Cloudflare is investigating an issue preventing some Access one-time PIN (OTP) emails from reaching customers who use certain email security gateways. Proofpoint users are currently the most affected. The sending IP address has been flagged by these gateways, causing OTP emails to be blocked. Cloudflare engineering is working to restore delivery. No other Access authentication is impacted as this time.

via statuspage

+0m

Aug 31, 2026 20:16

[investigating] Some customers using Proofpoint may experience delayed Cloudflare notifications and login codes. Proofpoint is temporarily deferring messages with an SMTP 421 4.7.0 response. Cloudflare will continue retrying delivery. Affected customers should ask their Proofpoint administrator to allowlist notify.cloudflare.com and Cloudflare IPs 104.30.16.2,104.30.16.3,104.30.16.4,104.30.16.5,104.30.16.6, and 104.30.16.7. If this cannot be configured locally, contact Proofpoint for additional support.

via statuspage

+31m

Aug 31, 2026 20:47

[identified] Some customers using Proofpoint may experience delayed Cloudflare notifications and login codes. Proofpoint is temporarily deferring messages with an SMTP 421 4.7.0 response. Cloudflare will continue retrying delivery. Affected customers should ask their Proofpoint administrator to allowlist notify.cloudflare.com and Cloudflare IPs 104.30.16.2,104.30.16.3,104.30.16.4,104.30.16.5,104.30.16.6, and 104.30.16.7. If this cannot be configured locally, contact Proofpoint for additional support.

via statuspage

+0m

Aug 31, 2026 20:47

[identified] The issue has been identified and a fix is being implemented.

via statuspage

+2m

Aug 31, 2026 20:49

[monitoring] Some customers using Proofpoint may experience delayed Cloudflare notifications and login codes. Proofpoint is temporarily deferring messages with an SMTP 421 4.7.0 response. Cloudflare will continue retrying delivery. Affected customers should ask their Proofpoint administrator to allowlist notify.cloudflare.com and Cloudflare IPs 104.30.16.2,104.30.16.3,104.30.16.4,104.30.16.5,104.30.16.6, and 104.30.16.7. If this cannot be configured locally, contact Proofpoint for additional support.

via statuspage

+0m

Aug 31, 2026 20:49

[monitoring] A fix has been implemented and we are monitoring the results.

via statuspage

+1h 14m

Aug 31, 2026 22:02

[resolved] This incident has been resolved an the developer documentation has also been updated to reflect the same information: https://developers.cloudflare.com/cloudflare-one/integrations/identity-providers/one-time-pin/#allow-otp-emails-through-your-email-gateway

via statuspage

+0m

Aug 31, 2026 22:02

[resolved] This incident has been resolved and the developer documentation has also been updated to reflect the same information: https://developers.cloudflare.com/cloudflare-one/integrations/identity-providers/one-time-pin/#allow-otp-emails-through-your-email-gateway

via statuspage

Lessons Learned

⚠Cloudflare has experienced 367 incidents in the past year. This frequency suggests systemic reliability challenges that may warrant additional monitoring.

📊Incidents related to authentication, configuration, security have occurred 243 times across all providers in the past year. This is one of the most common failure categories in cloud infrastructure.

💡This incident is categorized as: Configuration Error, Security Incident, Authentication Issue. Consider implementing preventive measures specific to this failure category.