We wanted to do some troubleshooting steps just to isolate the issue that you are having.
1. Clear cache/cookies on your browser.
2. Try a different browser (Mozilla Firefox, Safari)
3. Do a speedtest to see network issues. (speedtest.net)
Are you able to have the inspect element open while you are using the dialer?
To access the inspect element console right click on a blank space in your browser:
If you could please send us a screenshot of this once the error occurs that would be great for us to investigate further.