User is sporadically seeing white screen on all browsers -- my site and Discourse Meta


#1

Hi,

I accidentally let my VPS disk fill up with old Docker containers, which prevented Discourse from starting. After removing them and freeing up space, I got my site back online. But a user reported a problem where my Discourse forum was still displaying a blank white screen in Chrome. I asked him to try the page force-reload key combos for Chrome, and that seemed to get it working for him. However, along the way I also asked him to test the site in Chrome’s incognito mode since that disables extensions that could be causing issues. He was never able to get my site to display in his Chrome incognito window, even after restarting Chrome and Windows and deleting his Chrome browser cache. For me, the same version of Chrome (Version 39.0.2171.95) on Linux works fine in both modes. The user was successfully able to browse Discourse Meta on his Chrome browser via incognito mode. Any ideas what else could be causing the problem?


(Sam Saffron) #2

try rebuilding again.

cd /var/discoruse
git pull
./launcher rebuild app

#3

Thanks for the reply Sam. I had tried one more rebuild after getting the site back online. But at any rate the user is now reporting that Chrome started working for him in incognito mode. Must have been some weird cache issue with Chrome, that’s all I can figure.


#5

The problem seems to continue sporadically. The user is diligent about testing on multiple browsers, and he is also checking to see if Discourse Meta loads for him too. He continues to have sporadic difficulties accessing my site and Discourse Meta from all his browsers: IE, Chrome, and Firefox. Here are the sort of logs I’m seeing from his IP during the time he contacted me that he was getting white screens on all his browsers.

IE10:

Expected ')'
Url: http://mysite.com/assets/application-10496c85f7a1c6925e619b977156bdf4.js
Line: 13
Column: 24649
Window Location: http://mysite.com/

Firefox 28:

ReferenceError: I18n is not defined
Url: http://mysite.com/assets/vendor-7854cc8d2b80c3de7a1f1f7fc18c078e.js
Line: 16
Window Location: http://mysite.com/

and

SyntaxError: missing : after property id
Url: http://mysite.com/assets/application-10496c85f7a1c6925e619b977156bdf4.js
Line: 3
Window Location: http://mysite.com/

Chrome 39:

Uncaught SyntaxError: Unexpected string
Url: http://mysite.com/assets/application-10496c85f7a1c6925e619b977156bdf4.js
Line: 8
Column: 69
Window Location: http://mysite.com/

(I can Pastebin additional backtrace and environment information if anyone is interested)

Then after a few hours the problem resolved itself. But this sort of report has been going on for days. Really weird.


(Jeff Atwood) #6

Does this user repro the white screen problem on meta?


#7

Yes, sporadically. If you want I can PM you his IP address.


(Jeff Atwood) #8

Is this user running anti virus or proxy software that would interfere with incoming Internet http requests? Can they try a different computer, or their phone?

Does it happen if they switch to a different browser they do not normally use?


#9

I don’t think he’s on a proxy, but I’ll ask about antivirus. He’s seeing the white screens sporadically on two different computers, one running Win7 and the other is Win8.

Another useful tidbit: He sent me screenshots, and the page title and favicon were visible in the browser tab.


(Jeff Atwood) #10

It is also possible some upstream proxy between him and us is interfering. The best way to validate is to use a phone and switch off wifi. That bypasses his computer, his browser, and his network.


#11

OK, thanks. I’ll suggest that to him and report back here.


#12

He says he is just using Avast antivirus. He tried it on a Windows 8.1 smartphone with mobile IE, and it wouldn’t work. And at the moment he is having trouble accessing my site with Firefox and IE on his desktop computers. This time I’m not seeing any error logs being generated during his failed attempts.

The user mentioned that he has only had trouble with my site and occasionally with Discourse Meta, not other sites.


(cpradio) #13

Is he using the https everywhere extension?


(Jeff Atwood) #14

He said the problem persists in incognito mode in the OP, so that rules out plugins.


(cpradio) #15

Last I knew in Chrome you can definitely allow plugins in incognito mode… I can’t test Firefox right now

Other thoughts. Does he use a custom DNS provider, such as, Google or OpenDNS? Does he have a tunnel or proxy setup at the router level?


#16

Possibly, but from what I can tell he’s not doing anything out of the ordinary with his browsers, and not a huge plugin user. And sometimes is does work-- that’s the most frustrating thing about trying to debug this. Sometimes it works in Chrome, sometimes only in a regular Chrome sessions and not incognito, sometimes the other way around, sometimes only in Firefox, sometimes not in FF, etc.

I don’t think so, but I guess it’s worth checking. However, if it was a DNS problem, I don’t think he would be seeing my site’s name and favicon in his browser tabs?

Nope.

Thanks for the continued help with this, guys!


#17

I was wrong, he is using Google DNS. But again, it doesn’t seem like a problem resolving the name rather but the connection getting interrupted somehow.


(cpradio) #18

Well you do have multiple sources of you are using a cdn. Have him disable Google DNS to see if the issue clears itself or gets worse.


(Abdul Munim Zahid) #19

Today i was also unable to access Meta and my own discourse site from Safari and Maxthon Browser on a mac. Though both the sites worked fine on chrome.
and yep, it was a total whitescreen.

EDIT 2: oh and on Chrome i have a proxy set up but not on the other browsers.

EDIT: Im using google DNS.


#20

Hi again, my user continues to see erratic behavior. He tried switching from Google DNS to Advantage DNS, and it makes no difference. Sometimes it works on some browsers but not others, sometimes on none of them, and then later it will sometimes work on other browsers or even all browsers. The problem only occurs on my site and Meta. I don’t know what else to recommend.


#21

A little bit more information: The user is on a satellite internet connection. So that probably explains the seemingly erratic variations in viewing Discourse forums. He also says that he learned that his provider actively blocks 3rd party DNS services, which is why changing DNS providers made no difference.

So I think we now have a decent idea of what is happening. The user’s internet connection isn’t optimal, with the latency and possible errors inherent to a satellite connection. The provider is probably using abnormal settings at the TCP/IP layer as well, I imagine. But at the same time, the user doesn’t have trouble with other sites; as a matter of fact he is also a long-time user at another old style non-Discourse forum that I operate, and he never has issues with it. So I wonder if anything else can be done to make Discourse more robust with a sub-standard internet connection?