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How to Troubleshoot VoIP Calls That Fail After a PBX Certificate Renewal

11/10/2026

A certificate change can affect SIP TLS trust, hostname matching, chain completeness, or the phones’ trust stores.

Checks to make

Check PBX and handset logs, certificate names and chain, expiry, and provisioning status. Test registration and calls with a controlled device, and confirm whether intermediate certificates are required before rolling the certificate back.

When to get help

Voice support can review PBX certificate and endpoint trust behavior. Informatix Systems can assess the symptoms, evidence, and next steps. Contact Informatix Systems to discuss this issue.