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The table below contains some possible problems you may experience during the WCS server operation and recommendations to solve these issues. Please direct all technical questions related to configuration and functioning of Web Call Server to the technical support forum at or to



WCS server does not start

1. Make sure the server process is created.

2. Check logs server_logs/flashphoner.log for errors.

3. Make sure the name of your server host (Linux command 'hostname') correctly resolves to the IP address in /etc/hosts. The ping yourhost command must work, where yourhost is the name of your host displayed by the 'hostname' Linux command.

4. Check free disk space

WCS server does not accepts web client connections

1. Check free dick space

2. Check server logs for errors.

3. Make sure you have activated the license.

4. Check the Websocket port of the server (by default 8080) using the telnet command. Make sure the server uses this specific port for Websocket. To do this, you can use the 'netstat' Linux command and check the ws_port server setting.

5. Make a traffic dump and check if the Websocket traffic is running through.

Registration on the SIP server does not work

1. Check server logs for errors.

2. Make sure the SIP port range on the WCS server (by default 30000-31000) is openin Firewall, and if the WCS server is behind NAT additionally check that UDP packets sent to the external IP address reach the corresponding ports of the WCS server. Check port_from and port_to settings of the SIP port range.

3. Make a traffic dump and check if SIP traffic is running through.

One-way audio during a WebRTC-SIP call or completely no audio

Configure extended logging with client_dump_level=2 and check the logs and traffic dumps created after a test call followed by disconnect of the user. Make sure SIP, RTP and WebRTC traffic flows normally and there are no serious errors on the side of the web browser.

Lack of audio or video stream when working with streaming video and WebRTC

Make traffic dumps. Make sure WebRTC traffic flows normally and there are no serious errors on the side of the web browser.

Emergency shutdown of the server. The server stopped responding to requests.

1. Check if the server process is alive.

2. If there is no server process, check crash dumps in the logs directory of the server. Such dumps may look like error3677.log, where 3677 is the PID of the server process that was shut down. Send these dumps to the Flashphoner technical support.

3. If the server process is alive while the server looks not responding and does not process connections, make a dump of system streams of the server using the jstack command. Send this dump to the Flashphoner technical support along with the server logs.