How to allow ZIP files to be sent to your mailing list
Mail-List.com will alway reject email messages with the following types of attachments
BAT BTM CMD COM CPL DLL EXE LNK MSI PIF PRF REG SCR VBS URL
So if somebody emails an attachment called workday.bat, that message will be rejected back to the sender.
In addition, Mail-List.com will remove attachments with the following types
7Z ACE ARJ BZ BZ2 CAB GZ GZIP ISO JAR LZH TAR UUE XZ Z ZIP
These are various forms of compressed files and folders. That is, the one file attached, expands to many files. These sorts of files can be difficult to scan for viruses.
So if somebody emails an attachment called workday.zip, the email message will go to the mailing list, but not the attachment.