CSV can't validate

When I try to upload a csv file using

text/csv

text/csv

it never validates. The temp file has a .txt estension. Any idea?

Forms\Components\FileUpload::make('import_file')
->label('Import CSV')
->disk('local')
->acceptedFileTypes(['text/csv'])
->preserveFilenames(),

Forms\Components\FileUpload::make('import_file')
->label('Import CSV')
->disk('local')
->acceptedFileTypes(['text/csv'])
->preserveFilenames(),

CSV can't validate - Filament