pyTube downloaded music cannot be used in reaper

Question

I used pytube to donwload a playlist I created in YouTube. All files can be played by media players I tried (Classic Media Player, VLC Media Player, Windows Media Player), but for some reason reaper cannot import them. Does anyone have an idea why is this happening?

This was the code I used

from pytube import Playlist, YouTube
from pathlib import Path

actual = Path.cwd()
guerilla = Playlist("https://www.youtube.com/playlist?list=PL8ig_PduC0sKgSva6_tzdfZCkLp7jdAFF")
ext = "mp3"

def checkAuthor(yt):
    if "-" not in yt.title:
        try:
            return yt.author.split(sep=" - ")[1]
        except IndexError:
            return yt.author
    else: return ""

for index, music in enumerate(guerilla):

    curr = YouTube(
        music,
        use_oauth=True,
        allow_oauth_cache=True
        )

    id = curr.streams.get_audio_only()

    Path.mkdir(filePath, exist_ok=True)
    filePath = actual / "music"
    name = str(index+1) + " " + checkAuthor(curr) + " - " + curr.title + "." + ext
    completePath = filePath/name
    curr.streams.filter(file_extension=ext)

    toDown = curr.streams.get_by_itag(id.itag)
    toDown.download(filePath,name, skip_existing=True)

I tried installing LAME, ffmpeg and VLC but none helped. Also I realized that I can use any other audiofiles I downloaded from the internet.