voiceover problem

I have used the voiceover facility for some time now with my home videos but on trying recently , after a break, I cannot get it to work. I enter the Window option and get the voiceover window but when I click on the button the countdown starts and I start the commentary I do not get a waveform and the voice has not been recorded. I have deleted preferences as suggested by other users but this does not make any difference . I am using FCP 10.4.5 and Mojave 10.14.3. Hope and appreciate any help.

Verify your mic is actually being recognized by the OS. Go to System Preferences, to Sound, make sure you can select the mic as an input option, and it is registering an audio level when you speak in to it.

Did you ever figure out the issue? I am experiencing the exact same problem.