Does "on vacation' mean you're away from home? If you're away from home, how are you connecting to the Internet? I'll assume Cox doesn't like to authenticate SMTP with an "outside" IP address. I could be wrong and you'd only need to change your server settings.
Okay...once again...you've piqued my curiosity. What are hotel ISP SMTP settings? How would these settings relate to Cox email service? Do hotel ISP settings involve your Cox username and password? I will, however, agree it doesn't work...nor should it work.