Please try the following steps to fix the issue:
Refresh the page
Try to open the link with another browser. We recommend to use Google Chrome's latest version. You can install Google Chrome browser from here.
Open the interview in Incognito- mode. The page will ask for a permission to use camera and microphone again. Click "Allow".
Shutdown your computer for 5 seconds.
If possible, try using another device to answer the interview.
You can also record answers to your device and send the videos to us and we can upload the videos for you. The easiest way to share large video files is via Google Drive or Dropbox. If you choose to share the videos with us, please name the files clearly (e.g. Question 1, Question 2), and let us know the name of the interview and which email address you have received the invitation to.