NameError: name 'guildticket' is not defined

Question

When I try to react with this reaction emoji on discord "🎮", i dont get the discord role i should get (Mitglied). Only "NameError: name 'guildticket' is not defined" comes out at the console. I don't know what I should do, maybe you can help me :)

import discord
from discord import Color, channel, client
from discord.ext import commands

bot = commands.Bot(command_prefix=".")

@bot.command()
async def open(ctx):
    global guildticket
    guildticket = ctx.guild
    embed = discord.Embed(
        colour=Color.red()
    )
    embed.add_field(name="j4nluca's Ticket Bot", value="Reagiere mit \":envelope_with_arrow:\", um ein Ticket zu erstellen")
    embed.set_footer(text="Das Ticket funktioniert nicht? Schreibe: !open")

    await ctx.channel.purge(limit=1)
    emoji = "📩"
    message = await ctx.send(embed=embed)
    await message.add_reaction(emoji=emoji)
    
@bot.event
async def on_ready():
    print("\"Blokki\'s Bot\" erfolgreich geladen")
    activity = discord.Activity(type=discord.ActivityType.watching, name="Blokkmonsta zu")
    await bot.change_presence(activity=activity, status=discord.Status.online)

@bot.event
async def on_reaction_add(reaction, user):
    if user.id != 901815052091416616:
        guild = guildticket
        channelexists = discord.utils.get(guild.text_channels,name=user.name.lower().replace("#",""))
        if channelexists:
            None
        else:
            botrole = discord.utils.get(guild.roles, id=901816835123576874)

            if reaction.emoji == '📩' :
                category = discord.utils.get(guild.categories, id=969921517985099790)
                channel = await guild.create_text_channel(name=f"{user.name}", category=category)
                await channel.set_permissions(user, view_channel=True)
                await channel.send(f"{botrole.mention}")
                await channel.send(f"**`Ticket von {user.name}`**")
                await channel.send("Bitte schildere uns der Einfachkeit halber dein Problem möglichst ausführlich.")
                await channel.send("Sollte sich dein Problem geklärt haben, nutze .close")
            if reaction.emoji == '🎮':
                roles = discord.utils.get(user.guild.roles, name='Mitglied')
                await user.add_roles(roles)
    ```
    ...

Answer 1

You need to define and initiate guildticket as an empty variable in the global scope.

import discord
from discord import Color, channel, client
from discord.ext import commands

bot = commands.Bot(command_prefix=".")
guildticket = '' # Uses empty string as example (assuming ctx.guild is a string)