Source note · Troubleshooting Teams Direct Routing
Microsoft response code 540998 with SIP 503 ('Service state: Inactive/DrainingTransactions') is expected while Microsoft SIP endpoints are down for maintenance, and normally needs no action. If it happens often, check that the SBC re-resolves DNS frequently, ideally every 15 minutes or more often.
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
- SIP 503 and Microsoft response codes - Microsoft Teams — Microsoft · tier 2 current vendor documentation · 540998 503 Service Unavailable - Service state: Inactive/DrainingTransactions
Cite this note
APA
WarmTransfer. (2026, September 25). Troubleshooting Teams Direct Routing: source note teams-direct-routing-troubleshooting-503-540998. WarmTransfer. https://warmtransfer.net/knowledge/claims/teams-direct-routing-troubleshooting-503-540998
BibTeX
@misc{warmtransfer-claim-teams-direct-routing-troubleshooting-503-540998,
title = {Troubleshooting Teams Direct Routing: source note teams-direct-routing-troubleshooting-503-540998},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/teams-direct-routing-troubleshooting-503-540998},
note = {Source note teams-direct-routing-troubleshooting-503-540998, checked 2026-09-25}
}