Additional features, settings, or issues not covered by specific Microsoft Teams categories
Hi GABRIEL,
Thank you for the post. From your description, I assume you use Teams for Education. Since team files are stored in its corresponding SharePoint site behind the scene, you can try to upload the file in SharePoint site to check if it works.
Besides, you can try to upload the file in Teams web version to check if it helps. While if it doesn't work, may I know the size of the csv file and your Teams client version? Also, please capture a screenshot of the error message for us.
Regards,
Marvin