Running with Issues

[r-asou]

Hi author,

When I tried to running your project in my local environment,
First I run ng build, then npm start to start this project.
Although it started, but it has some issues on it.
When I click start btn on screen, them my console show the following errors. and cant click stop btn.

main-6QZH7YMQ.js:7 ERROR DOMException: Requested device not found
handleError @ main-6QZH7YMQ.js:7
main-6QZH7YMQ.js:7 ERROR TypeError: Failed to construct 'MediaRecorder': parameter 1 is not of type 'MediaStream'.
at e. (main-6QZH7YMQ.js:7:269943)
at Generator.next ()
at main-6QZH7YMQ.js:1:806
at new t (polyfills-RT5I6R6G.js:2:2236)
at he (main-6QZH7YMQ.js:1:626)
at e.startRecording (main-6QZH7YMQ.js:7:269857)
at main-6QZH7YMQ.js:7:268583
at gd (main-6QZH7YMQ.js:7:77522)
at o (main-6QZH7YMQ.js:7:77707)
at HTMLButtonElement. (main-6QZH7YMQ.js:7:106099)