err_connection_refused

Thanks a bunch.  This solution worked.  It is magic.

It works thank you so much <3333333333333333333333333333333333333333333333333333333

So, i came here after days of searching the solving of this problem. I had message: 

ERR_CONNECTION_TIMED_OUT

Nothing helped (hosts, reinstall, network settings reset, switch off extentions, cleaning cookies, incognito mode etc and etc ) except one thing: 

go to router settings, set there another DNS. What's interesting, popular google DNS did'nt helped, but Cloudflare's worked fine and i finally is able to use dropbox again. Update: later i tried again google's dns (8.8.8.8 and 8.8.4.4) and it worked at that moment. Advice: after changing dns wait for 1-2 minutes and only then try to access Dropbox.

So two steps:

1) Go to router (if you use it), change DNS settings to  1.1.1.1 and 1.0.0.1 (alternate). 

2) Also did the same in the Properties of Network adapter (tcp/ipv4 section). like on the bottom screenshot: 

So in my case it is something with default dns from my Internet provider (dropbox stopped working one day without any changes in the system). Manually changing DNS helped. Maybe it will help you too. Try. You can also try to use another public DNS servers, just google them. Because dropbox can work with some well or don't work. i'm just switching different dns till i get possibility to upload/ download files. (sometimes upload process starts from few tries. But still, it is now working overall)

I had the same issue. Turned out I set up OpenDNS some time ago, reverted to automatic in the IP v4 settings - now all is fine.

This was the fix for me, and I recommend everyone else who's having this problem to try the same. Why Dropbox staff couldn't recommend this in the first place is beyond me, but again, this finally solved my issue and restored my sanity. Thank you ayydot.