The default FailoverResponseCodes on a Teams online PSTN gateway are 408, 503 and 504, and setting the parameter overwrites the defaults rather than adding to them.

Checked 2026-09-25

Setting this parameter overwrites the default values, so if you want to include the default values, please add them to string.
Vendor
Microsoft
Product
Teams Phone Direct Routing
Subsystem
online PSTN gateway
Deployment
multi-tenant
Region
not restricted
Release range
MicrosoftTeams PowerShell module, current as of 2026-09-25
Checked
2026-09-25

Sources

Cite this note

APA

WarmTransfer. (2026, September 25). SIP trunk redundancy and failover design: source note sip-trunk-redundancy-design-ms-failover-codes. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-trunk-redundancy-design-ms-failover-codes

BibTeX

@misc{warmtransfer-claim-sip-trunk-redundancy-design-ms-failover-codes,
  title  = {SIP trunk redundancy and failover design: source note sip-trunk-redundancy-design-ms-failover-codes},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/sip-trunk-redundancy-design-ms-failover-codes},
  note   = {Source note sip-trunk-redundancy-design-ms-failover-codes, checked 2026-09-25}
}

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