Thanks for the pointers. Just to confirm: I tested the OVH FQDN sbc6.fr.sip.ovh from two independent clients on my side — a SIP app/softphone and an Asterisk server — and it works without any issue (registration + inbound/outbound calls). So DNS resolution and OVH routing look healthy outside of Vapi. My goal is to keep OVH’s failover by using the FQDN in Vapi. Could you please confirm: Does the ip/gateway field in Vapi (UI & API) currently accept hostnames/FQDNs? If yes, how often is the FQDN re‑resolved (on reconnect, per REGISTER/INVITE, TTL‑based)? Do you support SRV/NAPTR? If no, what’s the supported workaround for redundancy (multiple static IPs in one trunk, exact syntax, or separate trunks with a failover policy)? Noted your signaling IPs 44.229.228.186 and 44.238.177.138; if there are any others I should whitelist for my region, let me know. I can also share org/project + timestamps via DM if you want to check logs.