Tested this issue on Ubuntu 14.04 with chrome #57.0.2987.98 
These are the steps followed
1. On Ubuntu, launched chrome and signed into browser.
2. Go to "chrome://settings" and then click on "Advanced Sync settings" and choose 
   "Choose what to sync"

Observed that  i was able to change configurations in the "Advanced Sync settings"

goncalo.antonio.matos@ for better understanding could you please help us with screen-cast of this issue.  

Hi goncalo.antonio.matos@gmail.com, for better understand what's going on here, can I have the permission to look into your server side logs?

Ok i think i know how to reproduce:
1.Enable 2FA
2.Login to Chromium
3.Disable 2FA
4.Try to change said settings
And you should have the issue.

If you can't reproduce it, i can reproduce it on a screencast.

gangwu,yes you have my permission.

Thank you for providing more feedback. Adding requester "kkaluri@chromium.org" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

When you say Enable/Disable 2FA, what exactly are you doing?

https://myaccount.google.com/security , enabling "2 step verification", i think that's the english translation.

Screen recording: https://www.youtube.com/watch?v=oZ57J92sHb4

Just tried with another account and same thing. Is there any logging i could maybe provide you with? I've also tried purging chromium  and remove and configurations left but didn't worked.

I notice that you're using Chromium and not Chrome. Have you specified API keys?
 (https://www.chromium.org/developers/how-tos/api-keys) Sync won't work in Chromium without these, unlike Chrome. 

I've not, but i'm certain it has worked in the past.
I've just tried now with Chrome stable and it doesn't work either.

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Your video from #9 doesn't disable 2FA in the middle of the sign in flow, which seems contradictory to #4. The steps I observed from watching the video was something like:

1. Have a gmail account with 2FA enabled.
2. Sign into Chrome/Chromium.
3. Notice chrome://sync-internals hasn't started up sync correctly.
4. Loading sync settings from chrome://settings hangs.

Can you add a screenshot of chrome://signin-internals/ ?

Looking at server data from the 23rd, I see a bunch of control types (only asking for experiments and nigori) that seem to think they're successful. But there is no follow up GU for the rest of the data.

If I add a huge sleep to the first GU on my local machine, my chrome://sync-internals looks the exact same as in video from #9.

Can you confirm that my assertion in #14 was correct/incorrect? Are you disable 2FA on a different device? Or was that step not required to repro? I'm still a bit confused why #4 lists disabling 2FA.

You are correct, disabling 2FA is not required to reproduce the issue. At the time when i made that comment i tought that was what caused the issue but the issue is present regardless of it being enabled or not (the seperate account i mentioned i tested with does not have 2FA).

Hi goncalo.antonio.matos@gmail.com, 

Can you confirm following for me? 
1. This bug only happens on one of your machine, which is linux. correct?
2. On that machine, both chromium and chrome cannot sync. right?
3. What is your network environment? you machine is behind some firewall or gateway?

Hello, gangwu

1. This bug only happens on one of your machine, which is linux. correct? You are correct.
2. On that machine, both chromium and chrome cannot sync. right? Also correct
3. What is your network environment? you machine is behind some firewall or gateway? No firewall on this machine. It is ISP standard set up, isp router does DHCP, DNS requests are handled by the ISP dns server which is hardcoded within the router.

Unable to reproduce the issue on Ubuntu 14.04 with chrome #58.0.3029.96 as per steps mentioned in the video in comment #9

goncalo.antonio.matos@ could you update the chrome to latest version and retry the same steps on clean profile with no apps/extensions and let us know your observations.

Note:
Removing Needs-Bisect label for now, will add once again when we have proper repro steps to this issue.

Thank You...

Just tried with another account, and same thing. And freshly updated chrome, same version as yours.

As for steps to reproduce, i don't know. Currently by just signing in, i get this issue. Is there any cache i could clear to see if that could be the issue?

It looks like your machine can login but cannot connect to chrome sync server.
Is this a new machine? Do you change anything related to network recently?
Can you try to "ping clients4.google.com"?

Pinging works, here's the output:

$ ping clients4.google.com
PING clients.l.google.com (216.58.219.142) 56(84) bytes of data.
64 bytes from mia07s26-in-f142.1e100.net (216.58.219.142): icmp_seq=1 ttl=53 time=133 ms
64 bytes from mia07s26-in-f142.1e100.net (216.58.219.142): icmp_seq=2 ttl=53 time=132 ms
64 bytes from mia07s26-in-f142.1e100.net (216.58.219.142): icmp_seq=3 ttl=53 time=131 ms
64 bytes from mia07s26-in-f142.1e100.net (216.58.219.142): icmp_seq=4 ttl=53 time=131 ms
^C
--- clients.l.google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 131.668/132.351/133.484/0.806 ms

It is not a new machine, didn't change anything network wise AFAIK/remeber.

I don't know if it's of much help to debug the issue but i reproduced the issue with logging enabled: https://gist.github.com/duramato/1616bc54bd7053734147908146403790

from log, it shows a lot of "database is locked", so can you try launch chrome with "--user-data-dir=<newfolder>", for example, "chrome --user-data-dir=testfolder" to see the problem is still?

Same thing happen.
Log: https://gist.github.com/duramato/2f60c3e862578121105f643a4ab1bf81

Gang, does the new log shed any more light?

Hi goncalo.antonio.matos@gmail.com, sorry for delay reply, when you launch chrome by switch "--user-data-dir", like "chrome --user-data-dir=testfolder", can you take a screenshot for chrome://sync-internals again?