A Direct Routing wildcard certificate covers only one label: *.contoso.com matches sbc1.contoso.com but not customer10.sbc1.contoso.com, and an FQDN that does not match the CN or SAN needs a new certificate.

Checked 2026-09-25

You can't have multiple levels of subdomains under a wildcard.
Vendor
Microsoft
Product
Teams Phone Direct Routing
Subsystem
SBC certificate
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-wildcard-one-level. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-tls-handshake-failures-dr-wildcard-one-level

BibTeX

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

Read in context