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Twilio Connection Error

Questions & Answers

Twilio Error: 31003 (or, ICE negotiation with Twilio Failed)

This error indicates a loss of the connection between your Browser on your PC/Mac and the Twilio server, and if you were on an active phone call it was disconnected. The error is detected and reported by software running in your PC/Mac. The most common cause is a poor or intermittent Internet connection for your PC/Mac.

The 31003 error means you have a degraded Internet connection. This error is always associated with something in  your local environment and cannot be caused on the Twilio or turboDial side.

Read on for things you should try.

Run the test at to see if a call works there.
This test can usually detect problems with firewalls, and will sometimes detect degraded Internet connections.

If that test does not detect an issue then you may have an intermittent problem with your Internet connection or your PC.

Try re-booting your PC.
There may be background processes that are hogging the processor resources in your computer.

Try re-booting your LAN router and your Internet Access Modem.
Those devices are usually stable but can accumulate problems that can be cleared with a power-off followed a minute later by a power-on.

If you are connected to your LAN router via WiFi, try connecting using a cable instead. 
WiFi is subject to interference that may not be noticeable when you are browsing the web or reading email, but it can have a detrimental impact on voice calls.

Check your PC anti-virus and firewall settings.
Try turning both of them off to see if the problem goes away.

Check your local LAN Router configuration.
Your LAN Router may be blocking ports that Twilio needs for sending & receiving voice over the Internet. This problem has been seen most often in shared office arrangements, where your LAN Router is managed by the Office space provider on behalf of multiple tenants.

If you are logged in to your LAN using “Guest” credentials, try logging in as an officially known user.

If you continue seeing this problem you can ask your Office space provider to change the router configuration to support Twilio. Give them this test page: and ask them to configure the router so the test on that page succeeds.

When the test on that page fails due to port blocking by the Router your test will fail and a message will be displayed on the right side.

When running the test at  you may need to give your browser permission to access the microphone before the test can proceed,

If you are not able to have your LAN Router reconfigured to support Twilio then you can still use turboDial by placing your calls with a phone device other than ‘This PC’.