MIME type?

I’m getting this message when uploading a csv:
Invalid file. Use the below for debugging and when asking for support.

File: Array ( [name] => 301-redirect-file.csv [type] => unknown/exe [tmp_name] => /tmp/php9RsaR8 [error] => 0 [size] => 152 )

Am I doing something wrong? Thanks!

https://ww.wp.xz.cn/plugins/simple-301-redirects-addon-bulk-uploader/