Looking for advice on SIP 503 errors when traffic fails over to our secondary Singapore carrier.
Background
We manage 15 BYOC trunks across APAC. Primary carrier handles 90% of volume. Secondary is configured for failover via outbound routing rules.
Issue
When primary trunk hits capacity, Architect routes to secondary. Secondary immediately returns SIP 503 Service Unavailable. This does not happen during manual testing with low volume.
Troubleshooting
- Verified SIP credentials are active.
- Checked carrier logs; they show connection attempts but reject with 503.
- No firewall blocks detected between Genesys Cloud and secondary carrier edge.