if you’re sure there’s everything fine with your internet connection and you don’t use any tools that could block the network (LittleSnitch, MacKeeper,…) the first thing you should try is to update your eBay access token in the GarageSale preferences > Accounts.
Restart your Mac afterwards.
To get the latest beta version of GarageSale 7.0.17, please download it from here:
Yes, please find the most important details in this post: