The CSV upload issue you're experiencing might be due to some oddities in your original file. Here are some steps to fix this:
1. Remove commas, colons, and semicolons from your CSV data.
2. Ensure your CSV is UTF-8 encoded with comma-separated values.
3. Check that your file doesn't exceed 72 columns and 50,000 rows.
4. Remove any "created at" or "updated at" columns.
5. Try uploading your data to a public Google Sheet, then download it as a CSV and attempt the upload again.
6. Use a short file name for your CSV.
If the issue persists after trying these steps, you may need further assistance. In that case, please request to talk to a person for more in-depth support.