Web Pages not diplaying correctly

David Roth
David Roth used Ask the Experts™
on
Having a very strange issue whereby a few webpages do not display correctly on all computers in the office (including a mobile phone  - not on the company domain).
Two examples are speedtest and westin (see below)

speedtest.net page
westin.JPG
As such I am doubting the issue is related to any specific computer. Have spoken with the ISP (BT) and they say if they come and visit they will charge if it is not a BT related broadband issue. I am guessing the issue must be either on the router or somehow network related. I have tried local stuff like flushing the DNS, changing DNS to  8.8.8.8 etc but running out of ideas, apart from perhaps resetting the router. Apparently all was working fine up until a couple of days ago on this network. Any help/ideas would be appreciated.
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
David FavorFractional CTO
Distinguished Expert 2018

Commented:
Try displaying the page in Chrome.

Right click + inspect.

Select console.

Hit reload.

Look at errors produced.

Hint: My guess is some content from sites with problem are serving from some site which your Firewall has flagged as an attack IP + blocked the IP. If the site is a CDN where .css + .js + images live, then you'll see the exact problem you describe.

Be sure to check your Firewall rules. You can't just block an IP due to speed of connections, as one IP, serving content via HTTP2, may serve so many assets simultaneously, draconian Firewall rules may see this IP (incorrectly) as an attacker.

I've seen the behavior you're reporting several times + has tracked back to incorrect Firewall rules each time.
David RothTech Support Manager

Author

Commented:
Thanks David - will do. One thing I have noticed that seems to be common about the sites which are not showing properly, is that the browser is identifying them as not secure. I was just sent another (which I can load but again does not load at the customer site properly:

http://www.zinsseruk.com/product/

Note - no https...

I wonder if the answer lies here somehow?
David RothTech Support Manager

Author

Commented:
Hi David

I have run the inspect and the results are shown here. Unfortunately doesnt appear to be the firewall though as I have turned the firewall off (for testing) and the sites still don't load properly - any other suggestions?

inspect.JPG
Success in ‘20 With a Profitable Pricing Strategy

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden using our free interactive tool and use it to determine the right price for your IT services. Start calculating Now!

Try connecting a PC or even a laptop (as long as it exhibits the same issue) directly to your broadband modem. This will take your network out of the equation.

You might even want to power cycle the modem first (assuming you haven't tried that already)

Ken
David FavorFractional CTO
Distinguished Expert 2018

Commented:
Everywhere you see a red X is either a firewall or more likely... it appears... maybe some sort Ad Blocker is running.
David RothTech Support Manager

Author

Commented:
Thanks for your help and suggestions - all interesting and possible causes. However, having tried this morning, suddenly it is all working normally again and all web pages are working, so (somehow) I suspect the ISP - in this case BT - have been restricting some traffic and have now allowed ti through again. Strange as (obviously) they wont admit to anything....

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial