3CX Multi-Tenant Expert Needed – Troubleshoot Outbound SIP Calling

ob Description We are looking for an experienced 3CX / SIP VoIP specialist to troubleshoot an outbound calling issue on a 3CX Multi-Tenant system. Our 3CX system is operational and extensions are working, but outbound calls through one of our SIP trunks are failing. Current situation: 3CX Multi-Tenant environment SIP trunk provider: DIDForSale Inbound/system functionality appears operational 3CX correctly selects the outbound rule and SIP trunk Outbound INVITE is being sent to the provider Provider responds with SIP 480 Temporarily Unavailable 3CX Event ID: 12294 Need to verify DIDForSale IP whitelisting / termination authorization Need to review 3CX outbound rules and number formatting Need to review SIP trunk outbound parameters and caller ID headers Need to verify authentication and routing between 3CX and DIDForSale We have verbose 3CX Activity Logs and SIP traces available showing the failed calls. We are looking for someone who can remotely review the configuration, identify the problem, make the necessary corrections, and test outbound calling. Required experience: Strong experience with 3CX Experience with 3CX Multi-Tenant SIP trunk configuration and troubleshooting SIP INVITE/response analysis Caller ID / P-Asserted-Identity / Remote-Party-ID configuration Outbound rules and number manipulation IP-based SIP authentication / whitelisting Experience with DIDForSale is a plus This should hopefully be a relatively quick troubleshooting project for someone experienced with 3CX and SIP. Please include your 3CX experience, particularly with Multi-Tenant installations, when responding. We would like to troubleshoot this as soon as possible.