I've been getting the following message when attempting to upload my guest list file: An error has occurred while importing your contacts. Please confirm your file is an Excel document, noted with .xls in the file extension. ERROR  [Microsoft][ODBC Excel Driver] 'Sheet1$' is not a valid name. Make sure that it does not include invalid characters or punctuation and that it is not too long.
The file is in the correct format with the correct extension. There isn't a sheet named "Sheet1$", so I'm not sure what that's referring to. I've also made sure that there aren't any invalid characters (I've named the sheet "List").
I'm an avid excel user, I've tried different browsers on 2 different computers, and I'm still getting the same error. I've named the file different names, tried different sheet names, etc. I've also checked the help section, but there's nothing there on importing. Any help would be appreciated! Thanks!!