Add isinstance check for text channel.

cogs/commands/submission.py

@@ -9,6 +9,7 @@ from sqlalchemy.orm import Session
 
 from cogs.submission.verification_view import VerificationView
 from database_setup.sql_data_classes import Category, CategoryGroup, Guild, Submission, engine
+from main import logger
 from utilities.utils import GUILDS, autofill_categories, autofill_groups, submit_score
 
 
@@ -86,6 +87,14 @@ class SubmissionCog(commands.Cog):
                     "Registered Verification channel does not exist or was never registered. Contact server admins."
                 )
                 await interaction.response.send_message(error_response, ephemeral=True)
+                return
+
+            if not isinstance(channel, nextcord.TextChannel):
+                await interaction.response.send_message("An error happened with submission.")
+                logger.error(
+                    "Channel id %s in guild %s is does not correspond to a TextChannel.", channel.id, channel.guild.id
+                )
+                return
 
             # Send the verification message to admins
             verification_message = await channel.send(