This is a very complex situation. I am not certain what could be the root of this cause as there are several things which can affect and create this issue.
Firstly, you can begin by maintaining a good speed, if bandwidth is low it can be possible that it will not record your voice. Close all background actives.
Try changing your browser i.e. Chrome, Firefox.
In microphone setting of your browser, there will option to Add and Block.
Moreover, PTE Tutorials would provide remote support to help you can trace the issue, just contact at firstname.lastname@example.org regarding your issue.
Copy the website Link and paste in on Allow section. It should come like this
For Further assistance, please email us at support email address.