Hi @walkwalk88 be sure your smartphone or tablet is compatible - click to read. Be sure you've set up properly as the time comes from your phone. Here are the suggestions for when you've trouble syncing - click to read. The Zip was retired at least three years or so ago, so it might not get software updates at this point.
I still use the zip. In the app, on the Today screen, click the device icon in the upper left. When you click on the zip, it should let you click sync now. If the zip isn't listed in your devices, then I have no idea.