When the Microsoft SIP proxy sends a REFER, the SBC must send the new INVITE back to the SIP proxy, not to the PSTN, even for transfers to an external number, copying the Refer-To and Referred-By strings unchanged.

Checked 2026-09-25

Vendor
Microsoft
Product
Microsoft Teams Phone Direct Routing
Subsystem
transfer
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). Troubleshooting Teams call queues and auto attendants: source note teams-call-queue-troubleshooting-refer-invite-to-proxy. WarmTransfer. https://warmtransfer.net/knowledge/claims/teams-call-queue-troubleshooting-refer-invite-to-proxy

BibTeX

@misc{warmtransfer-claim-teams-call-queue-troubleshooting-refer-invite-to-proxy,
  title  = {Troubleshooting Teams call queues and auto attendants: source note teams-call-queue-troubleshooting-refer-invite-to-proxy},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/claims/teams-call-queue-troubleshooting-refer-invite-to-proxy},
  note   = {Source note teams-call-queue-troubleshooting-refer-invite-to-proxy, checked 2026-09-25}
}

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