Follow the below instruction for allowing the microphone on Google Chrome.
1. Go to the exam with check requirements and click on Next.
2. Click on Start system check.
3. At the top right side, click on the 3 dots as shown in the image below, then click Settings.
4. After, click on Privacy and Security on the left side and on the menu that opens click now on Site Settings.
6. Scroll down and select Microphone.
7. Select the Sites can ask to use your microphone option.
10. Go back to the System check page. Refresh the page.
11. Continue with the checks.