It can be failure like failed to make calls via the Yeastar gateways.
1. Check if the trunks are in good states.
2. Refer the interconnection guide to see if you have configured routes well.
3. Refer the case in this page: Gateway Call & Interconnection Failure Troubleshooting Content
If the issue persists after the above steps, try to get the following information and post it to our support.
1. Problem description
2. The result of the each step in the checklist
3. The screenshot of the route with problem.
4. The screenshot of the route list.
5. Get the Asterisk CLI log followed by this guide: How to Capture Asterisk CLI logs for Yeastar Devices
6. Get the PCAP capture followed by this guide: How to Get PCAP Dump Capture