Resolve AWS DNS Reputation ASAP

We are looking for an experienced DNS and domain reputation specialist to help resolve an ongoing production issue affecting users on certain mobile networks (specifically T-Mobile).

The specific error users see is:
DNS_PROBE_FINISHED_NXDOMAIN

Our platform is hosted on AWS (Route 53 + ALB / CloudFront). DNS is correctly configured and resolves properly on most networks (Google DNS, Quad9, etc.). Our domain reputation has already been reviewed and corrected by major security providers. However, users on T-Mobile are still experiencing DNS-based blocking or resolution issues.

This appears to be related to carrier-level DNS filtering or residual reputation/security classification behavior — not core infrastructure misconfiguration.

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Scope of Work
• Diagnose carrier-level DNS blocking behavior
• Analyze domain resolution differences across networks
• Validate CloudFront / ALB / TLS configuration
• Identify why T-Mobile resolvers still fail despite corrected reputation
• Recommend and implement a permanent production-grade solution
• Provide guidance to prevent future reputation-related disruptions

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Required Experience
• Advanced DNS troubleshooting (authoritative vs recursive)
• AWS Route 53
• CloudFront + ALB architecture
• Domain reputation systems (Cisco Umbrella, Norton, etc.)
• Carrier DNS filtering behavior
• Web security / phishing false-positive mitigation

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Important Context
• Production SaaS application
• Real-time user access required
• Reputation issues have been resolved, but access problems persist on T-Mobile
• Looking for rapid diagnosis and a permanent fix

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If you have experience resolving carrier-level DNS filtering or persistent domain reputation issues, please share:
• Relevant experience
• Similar cases handled
• Proposed approach
• Estimated timeline

We are ready to move quickly.