Swimbot Error

Traceback (most recent call last):
  File "/home/pi/.local/lib/python3.7/site-packages/discord/ext/commands/core.py", line 85, in wrapped
    ret = await coro(*args, **kwargs)
  File "/home/pi/Swimbot/whois.py", line 232, in whois
    embed = discord.Embed(title= f'**{ctx.message.guild.get_member(ctx.message.raw_mentions[0]).name}**', description= f'Current activity: **{ctx.message.guild.get_member(ctx.message.raw_mentions[0]).activity}**\nHighest role in server: **{ctx.message.guild.get_member(ctx.message.raw_mentions[0]).top_role}**', timestamp=ctx.message.created_at, color=discord.Colour.from_hsv(random.random(), 1, 1))
AttributeError: 'NoneType' object has no attribute 'name'