Hi,
The current version of the plugin checks the allowed file mime types before uploading by using the function get_allowed_mime_types() provided by WordPress. If your site setup or hosting provider has limited those allowed types, it’s possible that you are not able to upload a xlsx spreadsheet because of that (xlsx is allowed by default in WordPress).
In the plugin settings, Allow more file types -tab, you can allow more file types. Could you please choose 1 for “Number of custom file types”, check the checkbox for “Custom file type 1 active” and add “.xlsx” and “application/vnd.openxmlformats-officedocument.spreadsheetml.sheet” as values and try the upload again?
After that, it’s still possible that your site’s technical implementation or hosting provider overrides that setting, but this much can be done by the plugin itself.
You could also test the file you have with for example here https://mimetype.io/ to check the file mime type, just to be sure that it is “application/vnd.openxmlformats-officedocument.spreadsheetml.sheet”.
If you end up in a situation where you can’t upload xlsx files anymore, please accept my apologies. The current functionality is like that for maximum security. If any new information comes up, let me know, and I’ll try to help.
