Can’t install custom content with MacBook Pro.

I just reinstalled My Sims three into my new MacBook Pro and I cannot install custom content for the game. Every time I try to install it. It doesn’t work instead I get a message saying “important message there is a problem connecting to the server. Please ensure your Internet connection is active. If the Problem persists try again  later.” So I try to install it as much as possible But I get the same message over and over again. I want to install the custom content to my game to make it look more fun but no luck. Any suggestions To make it work without going through a hard process or bringing the viruses into the laptop. What will you suggest and please I need help. Thank you.