If the caller isn’t being heard, it’s usually an audio path issue. A couple of things to check:
• Make sure the SIP trunk is registered and supports two-way audio (RTP flow).
• Check if the correct codec (PCMU/PCMA/Opus) is enabled on both sides.
• Sometimes firewall/NAT settings block the inbound audio stream — worth checking your VoIP/SBC logs.
If you’d like, I can help you debug it step by step and get the audio flowing. You can also reach me on WhatsApp for quicker support: +2348101488169