title: User.mutual_guilds returning an empty list
body: <p>I decided to code another bot, but this time I coded it with an on_message support function. It worked perfectly fine until I decided to let the user choose which Server the problem relates to. So, i passed ctx (basically the message), and used <code>self.ctx.author.mutual_guilds</code>. And now, I ran into problems, because mutual_guilds returned an empty string. Can anybody please explain me why this happens?</p>
  <pre class="lang-py prettyprint-override"><code>class ChooseTicketServer(Select):
  
      def __init__(self, ctx, id):
          self.ctx = ctx
          self.id = id
          self.ServerOptions = [SelectOption(label=&quot;Test&quot;, value=&quot;Test&quot;)]
          self.servername = None
  
          print(self.ctx.author.mutual_guilds)
  
          for guild in self.ctx.author.mutual_guilds:
              self.ServerOptions.append(SelectOption(label = guild.name, value=f&quot;Server-ID: {guild.id}&quot;))
          
          super().__init__(placeholder=&quot;Choose the Server your Problem relates to...&quot;, min_values=1, max_values=1, options=self.ServerOptions)
  </code></pre>
  <pre class="lang-py prettyprint-override"><code>class SupportViewCreate(View):
      
      def __init__(self, *, timeout: float = 120.0, ctx, id):
          super().__init__(timeout=timeout)
          self.ctx = ctx
          self.id = id
          self.add_item(ChooseTicketServer(ctx=self.ctx, id=self.id))
  </code></pre>
  <pre class="lang-py prettyprint-override"><code>@bot.event
  async def on_message(ctx):
      if ctx.author == bot.user:
          return
      if not ctx.guild:
  
          id = random.randint(0, 99999999999999999999)
  
          while id in bot.activeSupportIDs:
              id = random.randint(0, 99999999999999999999)
          
          bot.activeSupportIDs.append(id)
  
          embed = Embed(title=&quot;Support Ticket&quot;, description=&quot;Please choose the Server your Problem relates to.&quot;, color=discord.Colour.green())
          embed.set_author(name=f&quot;{ctx.author.display_name}#{ctx.author.discriminator}&quot;, icon_url=ctx.author.avatar)
          embed.add_field(name=&quot;Ticket-ID: &quot;, value=f&quot;#{id}&quot;)
          embed.set_footer(text=f&quot;This is an automatically sent message from {bot.user.name}.&quot;)
  
          View = SupportViewCreate(ctx=ctx, id=id)
          await ctx.channel.send(embed=embed, view=View)
      
      else:
          await bot.process_commands(ctx)
  </code></pre>