Sync isn't working properly

I have read the guides; and as I have reported here The local sync is a huge frustration - #7 by cgrunenberg, I am following the suggested methods.
I am just getting “Connection to Server timed out” and “General CFSocket error” forever.

I have changed routers; I have changed networks, I even have changed countries over the years. My experience is always the same. It starts to sync for a while, then, shows up those errors, and completely stops.

I know the issue is not from the Bonjour technology itself because Bookends syncs pretty fast.