Can users upload csv files?

I’d like to create a pickaxe where the user can upload a csv file with data. The the user pastes some text in another field.
I want the bot to use the data from the csv file along with the text from the field to make a different list. (does that make sense?)
I get this error message when I upload the csv file as a user would (which is only 73kb)
What am I doing wrong?

Yes end-users can upload CSV files to the bots.

What is the error you receive when you try to upload a CSV file?