Microsoft lists a missing SBC certificate or missing intermediate certificates in the SBC's TLS handshake as a failure cause, and notes that only a packet capture may show that the certificate was never sent even when the configuration looks correct.

Checked 2026-09-25

Vendor
Microsoft
Product
Teams Phone Direct Routing
Subsystem
certificate chain
Deployment
multi-tenant
Region
not restricted
Release range
current as of 2026-09-25
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-dr-missing-intermediate. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-dr-missing-intermediate

BibTeX

@misc{warmtransfer-claim-sip-tls-handshake-failures-dr-missing-intermediate,
  title  = {SIP TLS handshake failures on trunks: source note sip-tls-handshake-failures-dr-missing-intermediate},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-dr-missing-intermediate},
  note   = {Source note sip-tls-handshake-failures-dr-missing-intermediate, checked 2026-09-25}
}

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