I've just installed jD 3.2.56 on J3.7.5 as I'd like to move away from using Docman. I've got a mixture of PDFs and Excel files to upload. I've added xls and xlsx to the permitted extensions in the usergroups settings, yet whenever I try to upload the spreadsheets from backend, they're rejected due to "invalid file extension."
What can I do to fix this? I really can't find any other settings to change this.