Could you please confirm what browser you`re using? I would also like to confirm if the buttons are not responsive or you`re not able to click on them at all? Thank you.
Could you please make sure you give Upwork permissions to access your microphone via your browser? You can click on the lock icon in your browser's address bar while you have Upwork site opened there. Then click Site Settings and then allow permissions for microphone. I'll also have the team follow up with you via a support ticket to make sure the issue is addressed.