Invalid File while trying load a pdf

Lately when I have tried uploading files to split it is telling me “invalid file.” Any help would be greatly appreciated. Thanks!

Hi Helpplease 1998, I’m Roseanne from Kami, could you email us at support@kamiapp.com from the email address associated with your Kami account and if possible share the file or one of the files you are having trouble with so we can investigate further?
Thanks