So I’m seeing a very odd bug with our BYOC SIP trunk integration where INVITE requests to our ServiceNow webhook endpoint are returning 403 Forbidden errors immediately after the Genesys Cloud Architect flow triggers the outbound call. The credentials are valid and the endpoint works via curl, but the SIP stack seems to be stripping the Authorization header. See SIP Trunk Configuration Docs for reference.
Check your JMeter load configuration before assuming the SIP stack is stripping headers. When testing BYOC trunks with high concurrency, the 403 Forbidden often stems from IP-based rate limiting or firewall rules triggered by the initial burst of INVITE packets, not header corruption. The Genesys Cloud documentation mentions that SIP trunks use static outbound IPs, so if your ServiceNow webhook has strict IP allow-listing, ensure all Genesys edge IPs are whitelisted.
Also, verify that the Authorization header is being passed in the HTTP request component of the Architect flow, not the SIP signaling itself. SIP and HTTP are separate protocols here. If you are using a custom Data Action to authenticate, remember that Data Actions have a default timeout of 3 seconds. If the auth service is slow under load, the flow might timeout and send a malformed request.
Try reducing the thread count in JMeter to 10 users. If the 403 stops, it is a capacity or rate-limit issue on the ServiceNow side, not a header stripping bug.