Source note · SIP 503 and trunk out-of-service failures
Microsoft's SIP 503 response-code guidance applies to Direct Routing PSTN calls and not to Calling Plan or Operator Connect deployments.
Checked 2026-09-25
- Vendor
- Microsoft
- Product
- Teams Phone Direct Routing
- Subsystem
- call failure codes
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-09-25
- Checked
- 2026-09-25
Sources
- SIP 503 and Microsoft response codes - Microsoft Teams — Microsoft · tier 2 current vendor documentation · Note at top of article
Cite this note
APA
WarmTransfer. (2026, September 25). SIP 503 and trunk out-of-service failures: source note sip-503-trunk-failures-dr-503-scope. WarmTransfer. https://warmtransfer.net/knowledge/claims/sip-503-trunk-failures-dr-503-scope
BibTeX
@misc{warmtransfer-claim-sip-503-trunk-failures-dr-503-scope,
title = {SIP 503 and trunk out-of-service failures: source note sip-503-trunk-failures-dr-503-scope},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/sip-503-trunk-failures-dr-503-scope},
note = {Source note sip-503-trunk-failures-dr-503-scope, checked 2026-09-25}
}