Try to explicitly clear own channel in force disconnect.

musicbot/cogs/music/__init__.py

@@ -559,11 +559,18 @@ async def _forcedisconnect(self, ctx):
         try:
             player = self.get_player(ctx.guild)
             player.queue.clear()
+            # Hopefully helps
+            player.channel_id = None
             await player.stop()
         except Exception as e:
             self.logger.error("Error forcedisconnecting")
             self.logger.exception(e)
-        await ctx.voice_client.disconnect(force=True)
+
+        if ctx.voice_client:
+            await ctx.voice_client.disconnect(force=True)
+        else:
+            self.logger.error("Voice client no longer exists")
+
         embed = discord.Embed(description='{disconnect.disconnected}', color=ctx.me.color)
         embed = ctx.localizer.format_embed(embed)
         await ctx.send(embed=embed)

musicbot/cogs/music/decorators.py

@@ -1,6 +1,7 @@
 import asyncio
 import functools
 import inspect
+import logging
 import math
 
 import discord
@@ -11,6 +12,8 @@
 from . import music_errors
 from .voice_client import BasicVoiceClient
 
+logger = logging.getLogger("musicbot").getChild("decorators")
+
 
 def require_voice_connection(should_connect=False):
     """Checks if the bot is in a valid voice channel for the command
@@ -50,9 +53,15 @@ async def ensure_voice_inner(self, ctx, *command_args, **kwargs):
                 await ctx.author.voice.channel.connect(cls=BasicVoiceClient)
 
             elif player.channel_id and int(player.channel_id) != ctx.author.voice.channel.id:
-                bot_channel = self.bot.get_channel(int(player.channel_id))
-                raise music_errors.UserInDifferentVoiceChannelError('You need to be in my voice channel',
-                                                                    channel=bot_channel)
+                if ctx.voice_client:
+                    bot_channel = self.bot.get_channel(int(player.channel_id))
+                    raise music_errors.UserInDifferentVoiceChannelError('You need to be in my voice channel',
+                                                                        channel=bot_channel)
+                else:
+                    # We are not connected anymore
+                    logger.debug("Voice client no longer exists, clear voice state")
+                    player.channel_id = None
+                    player._voice_state.clear()
 
             await func(self, ctx, *command_args, **kwargs)
 

requirements.txt

@@ -1,5 +1,5 @@
 discord.py == 2.3.*
-lavalink == 5.3.*
+lavalink == 5.5.*
 asyncio
 pyyaml
 BeautifulSoup4