- Firmware version: Any
- Model: S-Series
The SIP trunk (peer-type) on S50 shows unreachable. The SIP trunk works fine on the S50 of other sites.
The PCAP shows PBX sent OPTIONS packets, but no replies from the SIP trunk provider.
Client tries to contact the provider that the provider found the PBX public IP has been blacklisted by them. The solution is to add whitelist for the the PBX public IP.