OSError: [Errno 12] Cannot allocate memory Discord.py FFmpegPCMAudioでのエラーについて

Discord.pyでBotを作っており、VCを用いたコマンドを作成しているところ次のエラーが出ました。
メモリを確認しましたが特に問題はありませんでした。

動作環境 Ubuntu18.04LTS

コード

py
1def sound(ctx,num):
2        atk = r"/root/Bots/main/sampleaudio/12.mp3"
3        lose = r"/root/Bots/main/sampleaudio/3.mp3"
4        weapon= r"/root/Bots/main/sampleaudio/10.mp3"
5        geki = r"/root/Bots/main/sampleaudio/17.mp3"
6        ryuusei = r"/root/Bots/main/sampleaudio/8.mp3"
7        ban = r"/root/Bots/main/sampleaudio/7.mp3"
8        
9        sounds = (atk, lose, weapon, geki, ryuusei, ban)
10        try:
11         ctx.guild.voice_client.play(
12           FFmpegPCMAudio(
13               executable=r"/usr/bin/ffmpeg", 
14               source=sounds[num]))
15        except (discord.errors.ClientException, AttributeError):
16            return

エラー

py
1Traceback (most recent call last):
2  File "/root/Bots/main/taoru.py", line 216, in taoru
3    sound(ctx,0)
4  File "/root/Bots/main/taoru.py", line 34, in sound
5    FFmpegPCMAudio(
6  File "/root/.pyenv/versions/3.9.4/lib/python3.9/site-packages/discord/player.py", line 225, in __init__
7    super().__init__(source, executable=executable, args=args, **subprocess_kwargs)
8  File "/root/.pyenv/versions/3.9.4/lib/python3.9/site-packages/discord/player.py", line 138, in __init__
9    self._process = self._spawn_process(args, **kwargs)
10  File "/root/.pyenv/versions/3.9.4/lib/python3.9/site-packages/discord/player.py", line 144, in _spawn_process
11    process = subprocess.Popen(args, creationflags=CREATE_NO_WINDOW, **subprocess_kwargs)
12  File "/root/.pyenv/versions/3.9.4/lib/python3.9/subprocess.py", line 951, in __init__
13    self._execute_child(args, executable, preexec_fn, close_fds,
14  File "/root/.pyenv/versions/3.9.4/lib/python3.9/subprocess.py", line 1754, in _execute_child
15    self.pid = _posixsubprocess.fork_exec(
16OSError: [Errno 12] Cannot allocate memory