App force closes when I click the Mp3 download option

[dongentle2]

I have been trying to convert a youtube video to mp3 format. The app keeps crashing while the conversion is ongoing.

Describe the bug
The app crashes whenever I try to download a video in Mp3 format. Once I click the mp3 download button, it loads for some seconds before crashing.
See the attached video to understand better.

** Steps To Reproduce**

Launch the app
input the search words ( in my case I wanted to download rap devil)
click on your desired video from the search results.
click download mp3
starts converting and the error shows.

Expected behavior
When I carried out this operation, I expected it to convert and start the download but it kept crashing.

Screen recording
https://youtu.be/TeH_Z8DSo8g

Test Environment

Device: Infinix Hot 7 Pro
OS: Android 9.0
Software version: Music Downloader version 1.3.11

Logcat
Here is the full Inbuilt android logcat for the period

bugreport-H624EF-PPR1.180610.011-2019-07-02-14-47-10.zip