I am trying to import my guest list to my knot.com wedding website. It requires that I save the file in csv format. When I do so Excel says "This workbook contains features that will not work or may be removed if you save it in the selected file format. Do you want to continue?" I say yes but then when I go to upload my document the knot.com says "A general error has occurred, please try again." If I save the file in .xls format theknot.com tells me to please upload a file in the .csv format. Any suggestions on how to import my guest list?