Source note · Troubleshooting Teams Direct Routing
Microsoft's outbound-call article says that when Teams calls reach the SBC but fail with SIP 403 or 404, the PSTN provider is the most likely source, and you should contact the provider.
Checked 2026-09-25
- Vendor
- Microsoft
- Product
- Microsoft Teams Phone Direct Routing
- Subsystem
- sip-response-codes
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-25
- Checked
- 2026-09-25
Sources
- Issues with outbound calls - Microsoft Teams — Microsoft · tier 2 current vendor documentation · Connection to the SBC not established > Cause 2 / Resolution 2
Cite this note
APA
WarmTransfer. (2026, September 25). Troubleshooting Teams Direct Routing: source note teams-direct-routing-troubleshooting-403-pstn-provider. WarmTransfer. https://warmtransfer.net/knowledge/claims/teams-direct-routing-troubleshooting-403-pstn-provider
BibTeX
@misc{warmtransfer-claim-teams-direct-routing-troubleshooting-403-pstn-provider,
title = {Troubleshooting Teams Direct Routing: source note teams-direct-routing-troubleshooting-403-pstn-provider},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/teams-direct-routing-troubleshooting-403-pstn-provider},
note = {Source note teams-direct-routing-troubleshooting-403-pstn-provider, checked 2026-09-25}
}