Bug Page Cannot Be Loaded Error

[Tom.G]

Frustrating! I very occassionally get the same un-informative msg. Here, it usually, but not always, is an Internet problem. The worst part is that msg. seems to be a "last resort, catchall, generic" response.

From both personal experience and much online research time, here are the possibilities/conclusions I've come to, in no particular order:

Likely Causes:
1) A DNS problem
2) Page is truly not available on server due to a server problem
3) A dropped data packet from site to you
4) The communication stack on your computer got confused/corrupted
5) The browser cache is corrupted
6) Insufficient memory when browser asks for more storage
. . (too many programs or tabs open, OS bug?)
7) The browser has a bug
8) A few sites suggested using a VPN1) and 2) are usually corrected within minutes to days.
3) retry
4) reboot
5) and 6) clear cache & restart browser
7) and 8) ??

In my experience, an intermittent bug on the server side seems to be rare. Their usual error message says Page Not Found, not that you couldn't receive or display it.

Cheers,
Tom

 

[mfb]

Finally, we have presented evidence that the problem is server side. The best evidence is that a killing a stuck job made the problem go away temporarily. The next best is that multiple people report it. The next best is that it is intermittent. I don't see any evidence against the theory that the server is overwhelmed with the zillion scripts Xenforo wants to run.

The servers are certainly involved but it's not exclusively a server issue, or it would affect everyone equally (at the same time). Some users encounter that problem regularly. I haven't seen it even once. This thread is heavily biased towards users who see it, obviously.

 

[pbuk]

Their usual error message says Page Not Found, not that you couldn't receive or display it.

You need to appreciate that what you are seeing is an error message generated by the XenForo JavaScript running on the page when it fails to get a response to what is generally called an XMLHttpRequest. The routing of any requests to physicsforums.com are handled by the Cloudflare CDN which then forwards them to Greg's origin server. Cloudflare has some security (anti-DDoS) software which may be getting in the way, also Cloudflare has recently introduced a feature called 'Rocket Loader' which rewrites every HTML page that it delivers to use a proprietory asynchronous loader.

There are many things that all need to work, and the process is complicated further by browser caching (some of these scripts are delivered with a long cache time which means that unless the user manually clears the browser cache any changes Greg makes at his end, even if he pushes a cache invalidation to Cloudflare, are not going to be picked up locally).

It seems to me that the problems have started happening recently, and recently 2 things have happened:

• Cloudflare have implemented Rocket Loader
• PF has updated to a new version of XenForo

Tracking down whether the problem is due to one of these changes, a combination of the two changes, or some other interaction with another part of the system, is not trivial.

 

[Greg Bernhardt]

• Cloudflare have implemented Rocket Loader
• PF has updated to a new version of XenForo

Both of these ran across my mind. We do have a minor upgrade to do for XF which I may try to get to this weekend. For the Rocket Loader, we can try turning it off for a week and see if that helps, but generally, it has helped page loading.

 

[Vanadium 50]

A fact to add to the list - when it was doing this (well, the pause before the message), I opened a new window and a new private window. The two ""regular" windows displayed the error page. The private window displayed nothing.

 

[Vanadium 50]

One more data point. I went to the forum home page and it was taking a while to load - often a precursor to this message. I fired up Edge (I usually use Firefox) and immediately got the visitor page. I clicked the Log On button and...nothing. I got the message in the Firefox window, reloaded, and got the page. AND Edge was now displaying the login window.

 

[Greg Bernhardt]

Anyone still getting the error?

 

[PeroK]

Anyone still getting the error?

I'll be on my phone for a few weeks. The problem was only on the laptop.

 

[Vanadium 50]

Anyone still getting the error?

A few minutes ago.